lib/scanner: Use standard adler32 when we don't need rolling (#5556 )

* lib/scanner: Use standard adler32 when we don't need rolling Seems the rolling adler32 implementation is super slow when executed on large blocks, even tho I can't explain why. BenchmarkFind1MFile-16 100 18991667 ns/op 55.21 MB/s 398844 B/op 20 allocs/op BenchmarkBlock/adler32-131072/#00-16 200 9726519 ns/op 1078.06 MB/s 2654936 B/op 163 allocs/op BenchmarkBlock/bozo32-131072/#00-16 20 73435540 ns/op 142.79 MB/s 2654928 B/op 163 allocs/op BenchmarkBlock/buzhash32-131072/#00-16 20 61482005 ns/op 170.55 MB/s 2654928 B/op 163 allocs/op BenchmarkBlock/buzhash64-131072/#00-16 20 61673660 ns/op 170.02 MB/s 2654928 B/op 163 allocs/op BenchmarkBlock/vanilla-adler32-131072/#00-16 300 4377307 ns/op 2395.48 MB/s 2654935 B/op 163 allocs/op BenchmarkBlock/adler32-16777216/#00-16 2 544010100 ns/op 19.27 MB/s 65624 B/op 5 allocs/op BenchmarkBlock/bozo32-16777216/#00-16 1 4678108500 ns/op 2.24 MB/s 51970144 B/op 24 allocs/op BenchmarkBlock/buzhash32-16777216/#00-16 1 3880370700 ns/op 2.70 MB/s 51970144 B/op 24 allocs/op BenchmarkBlock/buzhash64-16777216/#00-16 1 3875911700 ns/op 2.71 MB/s 51970144 B/op 24 allocs/op BenchmarkBlock/vanilla-adler32-16777216/#00-16 300 4010279 ns/op 2614.72 MB/s 65624 B/op 5 allocs/op BenchmarkRoll/adler32-131072/#00-16 2000 974279 ns/op 134.53 MB/s 270 B/op 0 allocs/op BenchmarkRoll/bozo32-131072/#00-16 2000 791770 ns/op 165.54 MB/s 270 B/op 0 allocs/op BenchmarkRoll/buzhash32-131072/#00-16 2000 917409 ns/op 142.87 MB/s 270 B/op 0 allocs/op BenchmarkRoll/buzhash64-131072/#00-16 2000 881125 ns/op 148.76 MB/s 270 B/op 0 allocs/op BenchmarkRoll/adler32-16777216/#00-16 10 124000400 ns/op 135.30 MB/s 7548937 B/op 0 allocs/op BenchmarkRoll/bozo32-16777216/#00-16 10 118008080 ns/op 142.17 MB/s 7548928 B/op 0 allocs/op BenchmarkRoll/buzhash32-16777216/#00-16 10 126794440 ns/op 132.32 MB/s 7548928 B/op 0 allocs/op BenchmarkRoll/buzhash64-16777216/#00-16 10 126631960 ns/op 132.49 MB/s 7548928 B/op 0 allocs/op * Update benchmark_test.go * gofmt * fixup benchmark
lib/config, lib/model: Use path from locations to check disk space for db (#5525 )
2026-01-03 19:39:20 -05:00 · 2019-02-25 19:25:08 +01:00 · 2019-02-12 12:25:11 +00:00 · 2019-02-12 12:18:13 +00:00 · 2019-02-12 07:58:24 +01:00 · 2019-02-12 07:50:07 +01:00
2319 changed files with 76565 additions and 1127658 deletions
--- a/.github/CODEOWNERS
+++ b/.github/CODEOWNERS
@@ -0,0 +1,2 @@
+/AUTHORS    @calmh
+/*.md       @calmh
--- a/.github/ISSUE_TEMPLATE.md
+++ b/.github/ISSUE_TEMPLATE.md
@@ -0,0 +1,42 @@
+### DO NOT REPORT SECURITY ISSUES IN THIS ISSUE TRACKER
+
+Instead, contact security@syncthing.net directly - see
+https://syncthing.net/security.html for more information.
+
+### DO NOT POST SUPPORT REQUESTS OR GENERAL QUESTIONS IN THIS ISSUE TRACKER
+
+Please use the forum at https://forum.syncthing.net/ where a large number of
+helpful people hang out. This issue tracker is for reporting bugs or feature
+requests directly to the developers. Worst case you might get a short
+"that's a bug, please report it on GitHub" response on the forum, in which
+case we thank you for your patience and following our advice. :)
+
+### Please use the correct issue tracker
+
+If your problem relates to a Syncthing wrapper or [sub-project](https://github.com/syncthing) such as [Syncthing for Android](https://github.com/syncthing/syncthing-android/issues), [SyncTrayzor](https://github.com/canton7/synctrayzor) or the [documentation](https://github.com/syncthing/docs/issues), please use their respective issue trackers.
+
+### Does your log mention database corruption?
+
+If your Syncthing log reports panics because of database corruption it is most likely a fault with your system's storage or memory. Affected log entries will contain lines starting with `panic: leveldb`. You will need to delete the index database to clear this, by running `syncthing -reset-database`.
+
+### Please do post actual bug reports and feature requests.
+
+If your issue is a bug report, replace this boilerplate with a description
+of the problem, being sure to include at least:
+
+ - what happened,
+ - what you expected to happen instead, and
+ - any steps to reproduce the problem.
+
+Also fill out the version information below and add log output or
+screenshots as appropriate.
+
+If your issue is a feature request, simply replace this template text in
+its entirety.
+
+### Version Information
+
+Syncthing Version: v0.x.y
+OS Version: Windows 7 / Ubuntu 14.04 / ...
+Browser Version: (if applicable, for GUI issues)
+
--- a/.github/PULL_REQUEST_TEMPLATE.md
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -20,13 +20,8 @@ If this is a user visible change (including API and protocol changes), add a lin
 to the corresponding pull request on https://github.com/syncthing/docs or describe
 the documentation changes necessary.

-### Authorship
+## Authorship
+
+Your name and email will be added automatically to the AUTHORS file
+based on the commit metadata.

-Every author of a code contribution (Go, Javascript, HTML, CSS etc, with the
-possible exception of minor typo corrections and similar) is recorded in the
-AUTHORS and NICKS files and the in-GUI credits. If this is your first
-contribution, a maintainer will add you properly before accepting the
-contribution. You need not do so yourself or worry about the fact that the
-"authors" automated test fails. However, if your name (such as you want it
-presented in the credits) is not visible on your Github profile or in your
-commit messages, please assist by providing it here.
--- a/.gitignore
+++ b/.gitignore
@@ -17,3 +17,10 @@ RELEASE
 deb
 lib/auto/gui.files.go
 snapcraft.yaml
+prime/
+snap/
+parts/
+stage/
+*.snap
+*.bz2
+/repos
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -0,0 +1,5 @@
+service:
+  golangci-lint-version: 1.13.x
+  prepare:
+    - go run build.go assets
+    - GO111MODULE=on go mod vendor
--- a/.mailmap
+++ b/.mailmap
@@ -1 +0,0 @@
-NICKS
--- a/88
+++ b/88
@@ -1,39 +1,60 @@
 # This is the official list of Syncthing authors for copyright purposes.
-# The format is:
+#
+# THIS FILE IS MOSTLY AUTO GENERATED. IF YOU'VE MADE A COMMIT TO THE
+# REPOSITORY YOU WILL BE ADDED HERE AUTOMATICALLY WITHOUT THE NEED FOR
+# ANY MANUAL ACTION.
+#
+# That said, you are welcome to correct your name or add a nickname / GitHub
+# user name as appropriate. The format is:
 #
 #    Name Name Name (nickname) <email1@example.com> <email2@example.com>
 #
-# The NICKS list is auto generated from this file.
+# The in-GUI authors list is periodically automatically updated from the
+# contents of this file.
+#

 Aaron Bieber (qbit) <qbit@deftly.net>
-Adam Piggott (ProactiveServices) <aD@simplypeachy.co.uk> <simplypeachy@users.noreply.github.com> <ProactiveServices@users.noreply.github.com>
+Adam Piggott (ProactiveServices) <aD@simplypeachy.co.uk> <simplypeachy@users.noreply.github.com> <ProactiveServices@users.noreply.github.com> <adam@proactiveservices.co.uk>
 Adel Qalieh (adelq) <aqalieh95@gmail.com> <adelq@users.noreply.github.com>
 Alessandro G. (alessandro.g89) <alessandro.g89@gmail.com>
 Alexander Graf (alex2108) <register-github@alex-graf.de>
 Alexandre Viau (aviau) <alexandre@alexandreviau.net> <aviau@debian.org>
 Anderson Mesquita (andersonvom) <andersonvom@gmail.com>
+andresvia <andres.via@gmail.com>
 Andrew Dunham (andrew-d) <andrew@du.nham.ca>
-Andrey D (scienmind) <scintertech@cryptolab.net>
+Andrew Rabert (nvllsvm) <ar@nullsum.net> <6550543+nvllsvm@users.noreply.github.com>
+Andrey D (scienmind) <scintertech@cryptolab.net> <scienmind@users.noreply.github.com>
+andyleap <andyleap@gmail.com>
 Antoine Lamielle (0x010C) <antoine.lamielle@0x010c.fr> <gh@0x010c.fr>
 Antony Male (canton7) <antony.male@gmail.com>
+Aranjedeath <Aranjedeath@users.noreply.github.com>
 Arthur Axel fREW Schmidt (frioux) <frew@afoolishmanifesto.com> <frioux@gmail.com>
 Audrius Butkevicius (AudriusButkevicius) <audrius.butkevicius@gmail.com>
+BAHADIR YILMAZ <bahadiryilmaz32@gmail.com>
 Bart De Vries (mogwa1) <devriesb@gmail.com>
 Ben Curthoys (bencurthoys) <ben@bencurthoys.com>
 Ben Schulz (uok) <ueomkail@gmail.com> <uok@users.noreply.github.com>
 Ben Shepherd (benshep) <bjashepherd@gmail.com>
 Ben Sidhom (bsidhom) <bsidhom@gmail.com>
+Benedikt Heine (bebehei) <bebe@bebehei.de>
+Benedikt Morbach <benedikt.morbach@googlemail.com>
+Benno Fünfstück <benno.fuenfstueck@gmail.com>
 Benny Ng (tpng) <benny.tpng@gmail.com>
+Boris Rybalkin <ribalkin@gmail.com>
 Brandon Philips (philips) <brandon@ifup.org>
 Brendan Long (brendanlong) <self@brendanlong.com>
 Brian R. Becker (brbecker) <brbecker@gmail.com>
 Caleb Callaway (cqcallaw) <enlightened.despot@gmail.com>
 Carsten Hagemann (Moter8) <moter8@gmail.com>
-Cathryne Linenweaver (Cathryne) <cathryne.linenweaver@gmail.com> <Cathryne@users.noreply.github.com>
+Cathryne Linenweaver (Cathryne) <cathryne.linenweaver@gmail.com> <Cathryne@users.noreply.github.com> <katrinleinweber@MAC.local>
 Cedric Staniewski (xduugu) <cedric@gmx.ca>
 Chris Howie (cdhowie) <me@chrishowie.com>
 Chris Joel (cdata) <chris@scriptolo.gy>
+Chris Tonkinson <chris@masterbran.ch>
+chucic <chucic@seznam.cz>
 Colin Kennedy (moshen) <moshen.colin@gmail.com>
+Cromefire_ <tim.l@nghorst.net>
+Dale Visser <dale.visser@live.com>
 Daniel Bergmann (brgmnn) <dan.arne.bergmann@gmail.com> <brgmnn@users.noreply.github.com>
 Daniel Harte (norgeous) <daniel@harte.me> <daniel@danielharte.co.uk> <norgeous@users.noreply.github.com>
 Daniel Martí (mvdan) <mvdan@mvdan.cc>
@@ -41,8 +62,12 @@ Darshil Chanpura (dtchanpura) <dtchanpura@gmail.com> <dcprime314@gmail.com>
 David Rimmer (dinosore) <dinosore@dbrsoftware.co.uk>
 Denis A. (dva) <denisva@gmail.com>
 Dennis Wilson (snnd) <dw@risu.io>
+derekriemer <derek.riemer@colorado.edu>
+desbma <desbma@users.noreply.github.com>
+Dmitry Saveliev (dsaveliev) <d.e.saveliev@gmail.com>
 Dominik Heidler (asdil12) <dominik@heidler.eu>
 Elias Jarlebring (jarlebring) <jarlebring@gmail.com>
+Elliot Huffman <thelich2@gmail.com>
 Emil Hessman (ceh) <emil@hessman.se>
 Erik Meitner (WSGCSysadmin) <e.meitner@willystreet.coop>
 Federico Castagnini (facastagnini) <federico.castagnini@gmail.com>
@@ -51,25 +76,42 @@ Felix Unterpaintner (bigbear2nd) <bigbear2nd@gmail.com>
 Francois-Xavier Gsell (zukoo) <fxgsell@gmail.com>
 Frank Isemann (fti7) <frank@isemann.name>
 Gilli Sigurdsson (gillisig) <gilli@vx.is>
+Graham Miln (grahammiln) <graham.miln@dssw.co.uk> <graham.miln@miln.eu>
+Han Boetes <han@boetes.org>
+Harrison Jones (harrisonhjones) <harrisonhjones@users.noreply.github.com>
 Heiko Zuerker (Smiley73) <heiko@zuerker.org>
+Hugo Locurcio <hugo.locurcio@hugo.pro>
+Iain Barnett <iainspeed@gmail.com>
+Ian Johnson (anonymouse64) <ian.johnson@canonical.com> <person.uwsome@gmail.com>
+Iskander (Alex) Sharipov <quasilyte@gmail.com>
 Jaakko Hannikainen (jgke) <jgke@jgke.fi>
 Jacek Szafarkiewicz (hadogenes) <szafar@linux.pl>
 Jake Peterson (acogdev) <jake@acogdev.com>
 Jakob Borg (calmh) <jakob@nym.se> <jakob@kastelo.net>
 James Patterson (jpjp) <jamespatterson@operamail.com> <jpjp@users.noreply.github.com>
+janost <janost@tuta.io>
 Jaroslav Malec (dzarda) <dzardacz@gmail.com>
+jaseg <githubaccount@jaseg.net>
 Jaya Chithra (jayachithra) <s.k.jayachithra@gmail.com>
 Jens Diemer (jedie) <github.com@jensdiemer.de> <git@jensdiemer.de>
+Jerry Jacobs (xor-gate) <jerry.jacobs@xor-gate.org> <xor-gate@users.noreply.github.com>
 Jochen Voss (seehuhn) <voss@seehuhn.de>
+Johan Andersson <j@i19.se>
 Johan Vromans (sciurius) <jvromans@squirrel.nl>
+John Rinehart (fuzzybear3965) <johnrichardrinehart@gmail.com>
+Jonathan Cross <jcross@gmail.com>
 Jose Manuel Delicado (jmdaweb) <jmdaweb@hotmail.com> <jmdaweb@users.noreply.github.com>
+Jörg Thalheim <Mic92@users.noreply.github.com>
 Karol Różycki (krozycki) <rozycki.karol@gmail.com>
+Keith Turner <kturner@apache.org>
 Kelong Cong (kc1212) <kc04bc@gmx.com> <kc1212@users.noreply.github.com>
 Ken'ichi Kamada (kamadak) <kamada@nanohz.org>
 Kevin Allen (ironmig) <kma1660@gmail.com>
 Kevin White, Jr. (kwhite17) <kevinwhite1710@gmail.com>
+klemens <ka7@github.com>
 Kurt Fitzner (Kudalufi) <kurt@va1der.ca> <kurt.fitzner@gmail.com>
 Lars K.W. Gohlke (lkwg82) <lkwg82@gmx.de>
+Laurent Arnoud <laurent@spkdev.net>
 Laurent Etiemble (letiemble) <laurent.etiemble@gmail.com> <laurent.etiemble@monobjc.net>
 Leo Arias (elopio) <yo@elopio.net>
 Liu Siyuan (liusy182) <liusy182@gmail.com> <liusy182@hotmail.com>
@@ -79,42 +121,76 @@ Majed Abdulaziz (majedev) <majed.alhajry@gmail.com>
 Marc Laporte (marclaporte) <marc@marclaporte.com> <marc@laporte.name>
 Marc Pujol (kilburn) <kilburn@la3.org>
 Marcin Dziadus (marcindziadus) <dziadus.marcin@gmail.com>
+marco-m <marco.molteni@laposte.net>
 Mark Pulford (mpx) <mark@kyne.com.au>
 Mateusz Naściszewski (mateon1) <matin1111@wp.pl>
+Matic Potočnik <hairyfotr@gmail.com>
 Matt Burke (burkemw3) <mburke@amplify.com> <burkemw3@gmail.com>
+Matteo Ruina <matteo.ruina@gmail.com>
+Maurizio Tomasi <ziotom78@gmail.com>
 Max Schulze (kralo) <max.schulze@online.de> <kralo@users.noreply.github.com>
+MaximAL <almaximal@ya.ru>
+Maxime Thirouin <m@moox.io>
 Michael Jephcote (Rewt0r) <rewt0r@gmx.com> <Rewt0r@users.noreply.github.com>
 Michael Ploujnikov (plouj) <ploujj@gmail.com>
 Michael Tilli (pyfisch) <pyfisch@gmail.com>
+Mike Boone <mike@boonedocks.net>
+MikeLund <MikeLund@users.noreply.github.com>
 Nate Morrison (nrm21) <natemorrison@gmail.com>
+Nicholas Rishel (PrototypeNM1) <rishel.nick@gmail.com> <PrototypeNM1@users.noreply.github.com>
+Nico Stapelbroek <3368018+nstapelbroek@users.noreply.github.com>
+Nicolas Braud-Santoni <nicolas@braud-santoni.eu>
 Niels Peter Roest (Niller303) <nielsproest@hotmail.com> <seje.niels@hotmail.com>
+Nils Jakobi (thunderstorm99) <jakobi.nils@gmail.com>
+NoLooseEnds <jon.koslung@gmail.com>
+Oyebanji Jacob Mayowa <oyebanji05@gmail.com>
 Pascal Jungblut (pascalj) <github@pascalj.com> <mail@pascal-jungblut.com>
+Pawel Palenica (qepasa) <pawelpalenica11@gmail.com>
+Paweł Rozlach <vespian@users.noreply.github.com>
+perewa <cavalcante.ten@gmail.com>
+Peter Badida <KeyWeeUsr@users.noreply.github.com>
+Peter Dave Hello <hsu@peterdavehello.org>
 Peter Hoeg (peterhoeg) <peter@speartail.com>
+Peter Marquardt (wwwutz) <wwwutz@gmail.com> <wwwutz@googlemail.com>
+Phil Davis <phil.davis@inf.org>
 Philippe Schommers (filoozoom) <philippe@schommers.be>
 Phill Luby (pluby) <phill.luby@newredo.com>
+Pier Paolo Ramon <ramonpierre@gmail.com>
 Piotr Bejda (piobpl) <piotrb10@gmail.com>
+Pramodh KP (pramodhkp) <pramodh.p@directi.com> <1507241+pramodhkp@users.noreply.github.com>
+Richard Hartmann <RichiH@users.noreply.github.com>
 Robert Carosi (nov1n) <robert@carosi.nl>
 Roman Zaynetdinov (zaynetro) <romanznet@gmail.com>
 Ross Smith II (rasa) <ross@smithii.com>
+rubenbe <github-com-00ff86@vandamme.email>
 Ryan Sullivan (KayoticSully) <kayoticsully@gmail.com>
 Sacheendra Talluri (sacheendra) <sacheendra.t@gmail.com>
 Scott Klupfel (kluppy) <kluppy@going2blue.com>
 Sergey Mishin (ralder) <ralder@yandex.ru>
 Simon Frei (imsodin) <freisim93@gmail.com>
+Sly_tom_cat <slytomcat@mail.ru>
 Stefan Kuntz (Stefan-Code) <stefan.github@gmail.com> <Stefan.github@gmail.com>
-Stefan Tatschner (rumpelsepp) <stefan@sevenbyte.org> <rumpelsepp@sevenbyte.org>
+Stefan Tatschner (rumpelsepp) <stefan@sevenbyte.org> <rumpelsepp@sevenbyte.org> <stefan@rumpelsepp.org>
 Suhas Gundimeda (snugghash) <suhas.gundimeda@gmail.com> <snugghash@gmail.com>
+Taylor Khan (nelsonkhan) <nelsonkhan@gmail.com>
+Thomas Hipp <thomashipp@gmail.com>
 Tim Abell (timabell) <tim@timwise.co.uk>
 Tim Howes (timhowes) <timhowes@berkeley.edu>
 Tobias Nygren (tnn2) <tnn@nygren.pp.se>
+Tobias Tom (tobiastom) <t.tom@succont.de>
 Tomas Cerveny (kozec) <kozec@kozec.com>
+Tommy Thorn <tommy-github-email@thorn.ws>
 Tully Robinson (tojrobinson) <tully@tojr.org>
 Tyler Brazier (tylerbrazier) <tyler@tylerbrazier.com>
 Unrud (Unrud) <unrud@openaliasbox.org> <Unrud@users.noreply.github.com>
 Veeti Paananen (veeti) <veeti.paananen@rojekti.fi>
 Victor Buinsky (buinsky) <vix_booja@tut.by>
 Vil Brekin (Vilbrekin) <vilbrekin@gmail.com>
+Vladimir Rusinov <vrusinov@google.com>
+wangguoliang <liangcszzu@163.com>
 William A. Kennington III (wkennington) <william@wkennington.com>
 Wulf Weich (wweich) <wweich@users.noreply.github.com> <wweich@gmx.de> <wulf@weich-kr.de>
 Xavier O. (damajor) <damajor@gmail.com>
+xjtdy888 (xjtdy888) <xjtdy888@163.com>
 Yannic A. (eipiminus1) <eipiminusone+github@gmail.com> <eipiminus1@users.noreply.github.com>
+佛跳墙 <daoquan@qq.com>
--- a/CONDUCT.md
+++ b/CONDUCT.md
@@ -1,92 +1,73 @@
-## Conduct
+# Contributor Covenant Code of Conduct

-* We are committed to providing a friendly, safe and welcoming
-  environment for all, regardless of gender, sexual orientation,
-  disability, ethnicity, religion, or similar personal characteristic.
+## Our Pledge

-* On IRC, please avoid using overtly sexual nicknames or other nicknames
-  that might detract from a friendly, safe and welcoming environment for
-  all.
+In the interest of fostering an open and welcoming environment, we as
+contributors and maintainers pledge to making participation in our project and
+our community a harassment-free experience for everyone, regardless of age, body
+size, disability, ethnicity, gender identity and expression, level of experience,
+education, socio-economic status, nationality, personal appearance, race,
+religion, or sexual identity and orientation.

-* Please be kind and courteous. There's no need to be mean or rude.
+## Our Standards

-* Respect that people have differences of opinion and that every design
-  or implementation choice carries a trade-off and numerous costs. There
-  is seldom a right answer.
+Examples of behavior that contributes to creating a positive environment
+include:

-* Please keep unstructured critique to a minimum. If you have solid
-  ideas you want to experiment with, make a fork and see how it works.
+* Using welcoming and inclusive language
+* Being respectful of differing viewpoints and experiences
+* Gracefully accepting constructive criticism
+* Focusing on what is best for the community
+* Showing empathy towards other community members

-* We will exclude you from interaction if you insult, demean or harass
-  anyone. That is not welcome behaviour. We interpret the term
-  "harassment" as including the definition in the <a
-  href="http://citizencodeofconduct.org/">Citizen Code of Conduct</a>;
-  if you have any lack of clarity about what might be included in that
-  concept, please read their definition. In particular, we don't
-  tolerate behavior that excludes people in socially marginalized
-  groups.
+Examples of unacceptable behavior by participants include:

-* Private harassment is also unacceptable. No matter who you are, if you
-  feel you have been or are being harassed or made uncomfortable by a
-  community member, please contact one of the channel ops or any of the
-  Syncthing core team immediately. Whether you're a regular  contributor
-  or a newcomer, we care about making this community a safe place for
-  you and we've got your back.
+* The use of sexualized language or imagery and unwelcome sexual attention or
+  advances
+* Trolling, insulting/derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or electronic
+  address, without explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting

-* Likewise any spamming, trolling, flaming, baiting or other
-  attention-stealing behaviour is not welcome.
+## Our Responsibilities

-## Moderation
+Project maintainers are responsible for clarifying the standards of acceptable
+behavior and are expected to take appropriate and fair corrective action in
+response to any instances of unacceptable behavior.

-These are the policies for upholding our community's standards of
-conduct in our communication channels, most notably in Syncthing-related
-IRC channels and on the web forum.
+Project maintainers have the right and responsibility to remove, edit, or
+reject comments, commits, code, wiki edits, issues, and other contributions
+that are not aligned to this Code of Conduct, or to ban temporarily or
+permanently any contributor for other behaviors that they deem inappropriate,
+threatening, offensive, or harmful.

-1. Remarks that violate the Syncthing standards of conduct, including
-   hateful, hurtful, oppressive, or exclusionary remarks, are not
-   allowed. (Cursing is allowed, but never targeting another user, and
-   never in a hateful manner.)
+## Scope

-2. Remarks that moderators find inappropriate, whether listed in the
-   code of conduct or not, are also not allowed.
+This Code of Conduct applies both within project spaces and in public spaces
+when an individual is representing the project or its community. Examples of
+representing a project or community include using an official project e-mail
+address, posting via an official social media account, or acting as an appointed
+representative at an online or offline event. Representation of a project may be
+further defined and clarified by project maintainers.

-3. Moderators will first respond to such remarks with a warning.
+## Enforcement

-4. If the warning is unheeded, the user will be "kicked," i.e., kicked
-   out of the communication channel to cool off.
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported by contacting the project team at security@syncthing.net. All
+complaints will be reviewed and investigated and will result in a response that
+is deemed necessary and appropriate to the circumstances. The project team is
+obligated to maintain confidentiality with regard to the reporter of an incident.
+Further details of specific enforcement policies may be posted separately.

-5. If the user comes back and continues to make trouble, they will be
-   banned, i.e., indefinitely excluded.
+Project maintainers who do not follow or enforce the Code of Conduct in good
+faith may face temporary or permanent repercussions as determined by other
+members of the project's leadership.

-6. Moderators may choose at their discretion to un-ban the user if it
-   was a first offense and they offer the offended party a genuine
-   apology.
+## Attribution

-7. If a moderator bans someone and you think it was unjustified, please
-   take it up with that moderator, or with a different moderator, **in
-   private**. Complaints about bans in-channel are not allowed.
+This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
+available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html

-8. Moderators are held to a higher standard than other community
-   members. If a moderator creates an inappropriate situation, they
-   should expect less leeway than others.
-
-In the Syncthing community we strive to go the extra step to look out
-for each other. Don't just aim to be technically unimpeachable, try to
-be your best self. In particular, avoid flirting with offensive or
-sensitive issues, particularly if they're off-topic; this all too
-often leads to unnecessary fights, hurt feelings, and damaged trust;
-worse, it can drive people away from the community entirely.
-
-And if someone takes issue with something you said or did, resist the
-urge to be defensive. Just stop doing what it was they complained about
-and apologize. Even if you feel you were misinterpreted or unfairly
-accused, chances are good there was something you could've communicated
-better — remember that it's your responsibility to make your fellow
-community members comfortable. Everyone wants to get along and we are
-all here first and foremost because we want to talk about cool
-technology. You will find that people will be eager to assume good
-intent and forgive as long as you earn their trust.
-
-*Adapted from the [Rust Code of Conduct](https://github.com/rust-lang/rust/wiki/Note-development-policy#conduct)*
-
-*Adapted from the [Node.js Policy on Trolling](http://blog.izs.me/post/30036893703/policy-on-trolling)*
+[homepage]: https://www.contributor-covenant.org
--- a/32
+++ b/32
@@ -0,0 +1,32 @@
+FROM golang:1.11 AS builder
+
+WORKDIR /src
+COPY . .
+
+ENV CGO_ENABLED=0
+ENV BUILD_HOST=syncthing.net
+ENV BUILD_USER=docker
+RUN rm -f syncthing && go run build.go -no-upgrade build syncthing
+
+FROM alpine
+
+EXPOSE 8384 22000 21027/udp
+
+VOLUME ["/var/syncthing"]
+
+RUN apk add --no-cache ca-certificates su-exec
+
+COPY --from=builder /src/syncthing /bin/syncthing
+
+ENV PUID=1000 PGID=1000
+
+HEALTHCHECK --interval=1m --timeout=10s \
+  CMD nc -z localhost 8384 || exit 1
+
+ENTRYPOINT \
+  chown "${PUID}:${PGID}" /var/syncthing \
+  && su-exec "${PUID}:${PGID}" \
+     env HOME=/var/syncthing \
+     /bin/syncthing \
+       -home /var/syncthing/config \
+       -gui-address 0.0.0.0:8384
--- a/GOALS.md
+++ b/GOALS.md
@@ -36,7 +36,7 @@ or modification by unauthorized parties.

 Syncthing should be approachable, understandable and inclusive.

-> Complex concepts and maths form the base of Synchting's functionality.
+> Complex concepts and maths form the base of Syncthing's functionality.
 > This should nonetheless be abstracted or hidden to a degree where
 > Syncthing is usable by the general public.

--- a/ISSUE_TEMPLATE.md
+++ b/ISSUE_TEMPLATE.md
@@ -1,28 +0,0 @@
-Do not report security issues in this bug tracker. Instead, contact
-security@syncthing.net directly - see https://syncthing.net/security.html
-for more information.
-
-If your issue is a support request ("How do I get my devices to connect?"
-or similar), please use the support forum at https://forum.syncthing.net/
-where a large number of helpful people hang out. This issue tracker is for
-reporting bugs or feature requests directly to the developers.
-
-If your issue is a bug report, replace this boilerplate with a description
-of the problem, being sure to include at least:
-
- - what happened,
- - what you expected to happen instead, and
- - any steps to reproduce the problem.
-
-Also fill out the version information below and add log output or
-screenshots as appropriate.
-
-If your issue is a feature request, simply replace this template text in
-its entirety.
-
-### Version Information
-
-Syncthing Version: v0.x.y
-OS Version: Windows 7 / Ubuntu 14.04 / ...
-Browser Version: (if applicable, for GUI issues)
-
--- a/149
+++ b/149
@@ -1,149 +0,0 @@
-# This file maps email addresses used in commits to nicks used the changelog.
-# It is auto generated from the AUTHORS file by script/authors.go.
-
-0x010C <antoine.lamielle@0x010c.fr>
-0x010C <gh@0x010c.fr>
-acogdev <jake@acogdev.com>
-adelq <aqalieh95@gmail.com>
-adelq <adelq@users.noreply.github.com>
-alessandro.g89 <alessandro.g89@gmail.com>
-alex2108 <register-github@alex-graf.de>
-andersonvom <andersonvom@gmail.com>
-andrew-d <andrew@du.nham.ca>
-asdil12 <dominik@heidler.eu>
-AudriusButkevicius <audrius.butkevicius@gmail.com>
-aviau <alexandre@alexandreviau.net>
-aviau <aviau@debian.org>
-bencurthoys <ben@bencurthoys.com>
-benshep <bjashepherd@gmail.com>
-bigbear2nd <bigbear2nd@gmail.com>
-brbecker <brbecker@gmail.com>
-brendanlong <self@brendanlong.com>
-brgmnn <dan.arne.bergmann@gmail.com>
-brgmnn <brgmnn@users.noreply.github.com>
-bsidhom <bsidhom@gmail.com>
-buinsky <vix_booja@tut.by>
-burkemw3 <mburke@amplify.com>
-burkemw3 <burkemw3@gmail.com>
-calmh <jakob@nym.se>
-calmh <jakob@kastelo.net>
-canton7 <antony.male@gmail.com>
-Cathryne <cathryne.linenweaver@gmail.com>
-Cathryne <Cathryne@users.noreply.github.com>
-cdata <chris@scriptolo.gy>
-cdhowie <me@chrishowie.com>
-ceh <emil@hessman.se>
-cqcallaw <enlightened.despot@gmail.com>
-damajor <damajor@gmail.com>
-dinosore <dinosore@dbrsoftware.co.uk>
-dtchanpura <dtchanpura@gmail.com>
-dtchanpura <dcprime314@gmail.com>
-dva <denisva@gmail.com>
-dzarda <dzardacz@gmail.com>
-eipiminus1 <eipiminusone+github@gmail.com>
-eipiminus1 <eipiminus1@users.noreply.github.com>
-elopio <yo@elopio.net>
-facastagnini <federico.castagnini@gmail.com>
-filoozoom <philippe@schommers.be>
-frioux <frew@afoolishmanifesto.com>
-frioux <frioux@gmail.com>
-fti7 <frank@isemann.name>
-gillisig <gilli@vx.is>
-hadogenes <szafar@linux.pl>
-imsodin <freisim93@gmail.com>
-ironmig <kma1660@gmail.com>
-jarlebring <jarlebring@gmail.com>
-jayachithra <s.k.jayachithra@gmail.com>
-jedie <github.com@jensdiemer.de>
-jedie <git@jensdiemer.de>
-jgke <jgke@jgke.fi>
-jmdaweb <jmdaweb@hotmail.com>
-jmdaweb <jmdaweb@users.noreply.github.com>
-jpjp <jamespatterson@operamail.com>
-jpjp <jpjp@users.noreply.github.com>
-kamadak <kamada@nanohz.org>
-KayoticSully <kayoticsully@gmail.com>
-kc1212 <kc04bc@gmx.com>
-kc1212 <kc1212@users.noreply.github.com>
-kilburn <kilburn@la3.org>
-kluppy <kluppy@going2blue.com>
-kozec <kozec@kozec.com>
-kralo <max.schulze@online.de>
-kralo <kralo@users.noreply.github.com>
-krozycki <rozycki.karol@gmail.com>
-Kudalufi <kurt@va1der.ca>
-Kudalufi <kurt.fitzner@gmail.com>
-kwhite17 <kevinwhite1710@gmail.com>
-letiemble <laurent.etiemble@gmail.com>
-letiemble <laurent.etiemble@monobjc.net>
-liusy182 <liusy182@gmail.com>
-liusy182 <liusy182@hotmail.com>
-lkwg82 <lkwg82@gmx.de>
-LordLandon <lordlandon@gmail.com>
-majedev <majed.alhajry@gmail.com>
-marcindziadus <dziadus.marcin@gmail.com>
-marclaporte <marc@marclaporte.com>
-marclaporte <marc@laporte.name>
-mateon1 <matin1111@wp.pl>
-mogwa1 <devriesb@gmail.com>
-moshen <moshen.colin@gmail.com>
-Moter8 <moter8@gmail.com>
-mpx <mark@kyne.com.au>
-mvdan <mvdan@mvdan.cc>
-Niller303 <nielsproest@hotmail.com>
-Niller303 <seje.niels@hotmail.com>
-norgeous <daniel@harte.me>
-norgeous <daniel@danielharte.co.uk>
-norgeous <norgeous@users.noreply.github.com>
-nov1n <robert@carosi.nl>
-nrm21 <natemorrison@gmail.com>
-Nutomic <me@nutomic.com>
-pascalj <github@pascalj.com>
-pascalj <mail@pascal-jungblut.com>
-peterhoeg <peter@speartail.com>
-philips <brandon@ifup.org>
-piobpl <piotrb10@gmail.com>
-plouj <ploujj@gmail.com>
-pluby <phill.luby@newredo.com>
-ProactiveServices <aD@simplypeachy.co.uk>
-ProactiveServices <simplypeachy@users.noreply.github.com>
-ProactiveServices <ProactiveServices@users.noreply.github.com>
-pyfisch <pyfisch@gmail.com>
-qbit <qbit@deftly.net>
-ralder <ralder@yandex.ru>
-rasa <ross@smithii.com>
-Rewt0r <rewt0r@gmx.com>
-Rewt0r <Rewt0r@users.noreply.github.com>
-rumpelsepp <stefan@sevenbyte.org>
-rumpelsepp <rumpelsepp@sevenbyte.org>
-sacheendra <sacheendra.t@gmail.com>
-scienmind <scintertech@cryptolab.net>
-sciurius <jvromans@squirrel.nl>
-seehuhn <voss@seehuhn.de>
-Smiley73 <heiko@zuerker.org>
-snnd <dw@risu.io>
-snugghash <suhas.gundimeda@gmail.com>
-snugghash <snugghash@gmail.com>
-Stefan-Code <stefan.github@gmail.com>
-Stefan-Code <Stefan.github@gmail.com>
-timabell <tim@timwise.co.uk>
-timhowes <timhowes@berkeley.edu>
-tnn2 <tnn@nygren.pp.se>
-tojrobinson <tully@tojr.org>
-tpng <benny.tpng@gmail.com>
-tylerbrazier <tyler@tylerbrazier.com>
-Unrud <unrud@openaliasbox.org>
-Unrud <Unrud@users.noreply.github.com>
-uok <ueomkail@gmail.com>
-uok <uok@users.noreply.github.com>
-veeti <veeti.paananen@rojekti.fi>
-Vilbrekin <vilbrekin@gmail.com>
-wkennington <william@wkennington.com>
-WSGCSysadmin <e.meitner@willystreet.coop>
-wweich <wweich@users.noreply.github.com>
-wweich <wweich@gmx.de>
-wweich <wulf@weich-kr.de>
-xduugu <cedric@gmx.ca>
-zaynetro <romanznet@gmail.com>
-Zillode <zillode@zillode.be>
-zukoo <fxgsell@gmail.com>
--- a/README-Docker.md
+++ b/README-Docker.md
@@ -0,0 +1,43 @@
+# Docker Container for Syncthing
+
+Use the Dockerfile in this repo, or pull the `syncthing/syncthing` image
+from Docker Hub. Use volumes to have the synchronized files available on the
+host.
+
+The exposed volumes are by default:
+
+    /var/syncthing/config   - the configuration and index directory into the Container
+    /var/syncthing          - the default sync folder into the Container
+
+You can add more folders and map them as you prefer.
+
+Note that Syncthing runs as UID 1000 and GID 1000 by default. These may be
+altered with the ``PUID`` and ``PGID`` environment variables.
+
+Example usage:
+
+```
+$ docker pull syncthing/syncthing
+$ docker run -p 8384:8384 -p 22000:22000 \
+    -v /wherever/st-cfg:/var/syncthing/config \
+    -v /wherever/st-sync:/var/syncthing \
+    syncthing/syncthing:latest
+```
+
+Note that local device discovery will not work with the above command resulting
+in poor local transfer rates if local device addresses are not manually
+configured.
+
+To allow local discovery, the docker host network can be used instead:
+
+```
+$ docker pull syncthing/syncthing
+$ docker run --network=host \
+    -v /wherever/st-cfg:/var/syncthing/config \
+    -v /wherever/st-sync:/var/syncthing \
+    syncthing/syncthing:latest
+```
+
+Be aware that syncthing alone is now in control of what interfaces and ports it
+listens on. You can edit the syncthing configuration to change the defaults if
+there are conflicts.
--- a/README.md
+++ b/README.md
@@ -2,11 +2,10 @@

 ---

-[![Latest Linux & Cross Build](https://img.shields.io/jenkins/s/http/build.syncthing.net/syncthing.svg?style=flat-square&label=linux+%26+cross)](https://build.syncthing.net/job/syncthing/lastBuild/)
-[![Latest Windows Build](https://img.shields.io/jenkins/s/http/build.syncthing.net/syncthing-windows.svg?style=flat-square&label=windows)](https://build.syncthing.net/job/syncthing/lastBuild/)
-[![Latest Mac Build](https://img.shields.io/jenkins/s/http/build.syncthing.net/syncthing-mac.svg?style=flat-square&label=mac)](https://build.syncthing.net/job/syncthing/lastBuild/)
-[![Latest Solaris Build](https://img.shields.io/jenkins/s/http/build.syncthing.net/syncthing-solaris.svg?style=flat-square&label=solaris)](https://build.syncthing.net/job/syncthing/lastBuild/)
-[![API Documentation](https://img.shields.io/badge/api-Godoc-blue.svg?style=flat-square)](https://godoc.org/github.com/syncthing/syncthing)
+[![Latest Downloads](https://img.shields.io/badge/latest-downloads-brightgreen.svg?style=flat-square)](https://build.syncthing.net/latest/)
+[![Latest Linux & Cross Build](https://img.shields.io/teamcity/https/build.syncthing.net/s/Syncthing_BuildLinuxCross.svg?style=flat-square&label=linux+%26+cross+build)](https://build.syncthing.net/viewType.html?buildTypeId=Syncthing_BuildLinuxCross&guest=1)
+[![Latest Windows Build](https://img.shields.io/teamcity/https/build.syncthing.net/s/Syncthing_BuildWindows.svg?style=flat-square&label=windows+build)](https://build.syncthing.net/viewType.html?buildTypeId=Syncthing_BuildWindows&guest=1)
+[![Latest Mac Build](https://img.shields.io/teamcity/https/build.syncthing.net/s/Syncthing_BuildMac.svg?style=flat-square&label=mac+build)](https://build.syncthing.net/viewType.html?buildTypeId=Syncthing_BuildMac&guest=1)
 [![MPLv2 License](https://img.shields.io/badge/license-MPLv2-blue.svg?style=flat-square)](https://www.mozilla.org/MPL/2.0/)
 [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/88/badge)](https://bestpractices.coreinfrastructure.org/projects/88)
 [![Go Report Card](https://goreportcard.com/badge/github.com/syncthing/syncthing)](https://goreportcard.com/report/github.com/syncthing/syncthing)
@@ -21,36 +20,36 @@ commentary, see the full [Goals document][13].

 Syncthing should be:

-1. Safe From Data Loss
+1. **Safe From Data Loss**

   Protecting the user's data is paramount. We take every reasonable
   precaution to avoid corrupting the user's files.

-2. Secure Against Attackers
+2. **Secure Against Attackers**

   Again, protecting the user's data is paramount. Regardless of our other
   goals we must never allow the user's data to be susceptible to
   eavesdropping or modification by unauthorized parties.

-3. Easy to Use
+3. **Easy to Use**

   Syncthing should be approachable, understandable and inclusive.

-4. Automatic
+4. **Automatic**

   User interaction should be required only when absolutely necessary.

-5. Universally Available
+5. **Universally Available**

   Syncthing should run on every common computer. We are mindful that the
   latest technology is not always available to any given individual.

-6. For Individuals
+6. **For Individuals**

   Syncthing is primarily about empowering the individual user with safe,
   secure and easy to use file synchronization.

-7. Everything Else
+7. **Everything Else**

   There are many things we care about that don't make it on to the list. It
   is fine to optimize for these values, as long as they are not in conflict
@@ -88,8 +87,8 @@ D26E6ED000654A3E, available from https://syncthing.net/security.html and
 most key servers.

 There is also a built in automatic upgrade mechanism (disabled in some
-distribution channels) which uses a compiled in ECDSA signature. Mac OS
-X binaries are also properly code signed.
+distribution channels) which uses a compiled in ECDSA signature. macOS
+binaries are also properly code signed.

 ## Documentation

@@ -111,4 +110,5 @@ All code is licensed under the [MPLv2 License][7].
 [12]: https://www.bountysource.com/teams/syncthing/issues
 [13]: https://github.com/syncthing/syncthing/blob/master/GOALS.md
 [14]: assets/logo-text-128.png
-[15]: https://syncthing.net/ 
+[15]: https://syncthing.net/
+
--- a/assets/logo.ico
+++ b/assets/logo.ico
--- a/build.go
+++ b/build.go
@@ -34,17 +34,22 @@ import (
 )

 var (
-	versionRe     = regexp.MustCompile(`-[0-9]{1,3}-g[0-9a-f]{5,10}`)
-	goarch        string
-	goos          string
-	noupgrade     bool
-	version       string
-	goVersion     float64
-	race          bool
-	debug         = os.Getenv("BUILDDEBUG") != ""
-	noBuildGopath bool
-	extraTags     string
-	installSuffix string
+	versionRe        = regexp.MustCompile(`-[0-9]{1,3}-g[0-9a-f]{5,10}`)
+	goarch           string
+	goos             string
+	noupgrade        bool
+	version          string
+	goCmd            string
+	goVersion        float64
+	race             bool
+	debug            = os.Getenv("BUILDDEBUG") != ""
+	extraTags        string
+	installSuffix    string
+	pkgdir           string
+	cc               string
+	debugBinary      bool
+	timeout          = "120s"
+	gogoProtoVersion = "v1.2.0"
 )

 type target struct {
@@ -108,6 +113,14 @@ var targets = map[string]target{
 			{src: "etc/linux-systemd/system/syncthing-resume.service", dst: "deb/lib/systemd/system/syncthing-resume.service", perm: 0644},
 			{src: "etc/linux-systemd/user/syncthing.service", dst: "deb/usr/lib/systemd/user/syncthing.service", perm: 0644},
 			{src: "etc/firewall-ufw/syncthing", dst: "deb/etc/ufw/applications.d/syncthing", perm: 0644},
+			{src: "etc/linux-desktop/syncthing-start.desktop", dst: "deb/usr/share/applications/syncthing-start.desktop", perm: 0644},
+			{src: "etc/linux-desktop/syncthing-ui.desktop", dst: "deb/usr/share/applications/syncthing-ui.desktop", perm: 0644},
+			{src: "assets/logo-32.png", dst: "deb/usr/share/icons/hicolor/32x32/apps/syncthing.png", perm: 0644},
+			{src: "assets/logo-64.png", dst: "deb/usr/share/icons/hicolor/64x64/apps/syncthing.png", perm: 0644},
+			{src: "assets/logo-128.png", dst: "deb/usr/share/icons/hicolor/128x128/apps/syncthing.png", perm: 0644},
+			{src: "assets/logo-256.png", dst: "deb/usr/share/icons/hicolor/256x256/apps/syncthing.png", perm: 0644},
+			{src: "assets/logo-512.png", dst: "deb/usr/share/icons/hicolor/512x512/apps/syncthing.png", perm: 0644},
+			{src: "assets/logo-only.svg", dst: "deb/usr/share/icons/hicolor/scalable/apps/syncthing.svg", perm: 0644},
 		},
 	},
 	"stdiscosrv": {
@@ -120,13 +133,13 @@ var targets = map[string]target{
 		archiveFiles: []archiveFile{
 			{src: "{{binary}}", dst: "{{binary}}", perm: 0755},
 			{src: "cmd/stdiscosrv/README.md", dst: "README.txt", perm: 0644},
-			{src: "cmd/stdiscosrv/LICENSE", dst: "LICENSE.txt", perm: 0644},
+			{src: "LICENSE", dst: "LICENSE.txt", perm: 0644},
 			{src: "AUTHORS", dst: "AUTHORS.txt", perm: 0644},
 		},
 		installationFiles: []archiveFile{
 			{src: "{{binary}}", dst: "deb/usr/bin/{{binary}}", perm: 0755},
 			{src: "cmd/stdiscosrv/README.md", dst: "deb/usr/share/doc/syncthing-discosrv/README.txt", perm: 0644},
-			{src: "cmd/stdiscosrv/LICENSE", dst: "deb/usr/share/doc/syncthing-discosrv/LICENSE.txt", perm: 0644},
+			{src: "LICENSE", dst: "deb/usr/share/doc/syncthing-discosrv/LICENSE.txt", perm: 0644},
 			{src: "AUTHORS", dst: "deb/usr/share/doc/syncthing-discosrv/AUTHORS.txt", perm: 0644},
 			{src: "man/stdiscosrv.1", dst: "deb/usr/share/man/man1/stdiscosrv.1", perm: 0644},
 		},
@@ -143,12 +156,14 @@ var targets = map[string]target{
 			{src: "{{binary}}", dst: "{{binary}}", perm: 0755},
 			{src: "cmd/strelaysrv/README.md", dst: "README.txt", perm: 0644},
 			{src: "cmd/strelaysrv/LICENSE", dst: "LICENSE.txt", perm: 0644},
+			{src: "LICENSE", dst: "LICENSE.txt", perm: 0644},
 			{src: "AUTHORS", dst: "AUTHORS.txt", perm: 0644},
 		},
 		installationFiles: []archiveFile{
 			{src: "{{binary}}", dst: "deb/usr/bin/{{binary}}", perm: 0755},
 			{src: "cmd/strelaysrv/README.md", dst: "deb/usr/share/doc/syncthing-relaysrv/README.txt", perm: 0644},
 			{src: "cmd/strelaysrv/LICENSE", dst: "deb/usr/share/doc/syncthing-relaysrv/LICENSE.txt", perm: 0644},
+			{src: "LICENSE", dst: "deb/usr/share/doc/syncthing-relaysrv/LICENSE.txt", perm: 0644},
 			{src: "AUTHORS", dst: "deb/usr/share/doc/syncthing-relaysrv/AUTHORS.txt", perm: 0644},
 			{src: "man/strelaysrv.1", dst: "deb/usr/share/man/man1/strelaysrv.1", perm: 0644},
 		},
@@ -175,6 +190,19 @@ var targets = map[string]target{
 	},
 }

+// These are repos we need to clone to run "go generate"
+
+type dependencyRepo struct {
+	path   string
+	repo   string
+	commit string
+}
+
+var dependencyRepos = []dependencyRepo{
+	{path: "protobuf", repo: "https://github.com/gogo/protobuf.git", commit: gogoProtoVersion},
+	{path: "xdr", repo: "https://github.com/calmh/xdr.git", commit: "08e072f9cb16"},
+}
+
 func init() {
 	// The "syncthing" target includes a few more files found in the "etc"
 	// and "extra" dirs.
@@ -203,27 +231,6 @@ func main() {
 		}()
 	}

-	if gopath() == "" {
-		gopath, err := temporaryBuildDir()
-		if err != nil {
-			log.Fatal(err)
-		}
-		if !noBuildGopath {
-			lazyRebuildAssets()
-			if err := buildGOPATH(gopath); err != nil {
-				log.Fatal(err)
-			}
-		}
-		os.Setenv("GOPATH", gopath)
-		log.Println("GOPATH is", gopath)
-	}
-
-	// Set path to $GOPATH/bin:$PATH so that we can for sure find tools we
-	// might have installed during "build.go setup".
-	os.Setenv("PATH", fmt.Sprintf("%s%cbin%c%s", os.Getenv("GOPATH"), os.PathSeparator, os.PathListSeparator, os.Getenv("PATH")))
-
-	checkArchitecture()
-
 	// Invoking build.go with no parameters at all builds everything (incrementally),
 	// which is what you want for maximum error checking during development.
 	if flag.NArg() == 0 {
@@ -245,20 +252,8 @@ func main() {
 	}
 }

-func checkArchitecture() {
-	switch goarch {
-	case "386", "amd64", "arm", "arm64", "ppc64", "ppc64le", "mips", "mipsle":
-		break
-	default:
-		log.Printf("Unknown goarch %q; proceed with caution!", goarch)
-	}
-}
-
 func runCommand(cmd string, target target) {
 	switch cmd {
-	case "setup":
-		setup()
-
 	case "install":
 		var tags []string
 		if noupgrade {
@@ -306,9 +301,6 @@ func runCommand(cmd string, target target) {
 	case "snap":
 		buildSnap(target)

-	case "clean":
-		clean()
-
 	case "vet":
 		metalintShort()

@@ -321,13 +313,6 @@ func runCommand(cmd string, target target) {
 	case "version":
 		fmt.Println(getVersion())

-	case "gopath":
-		gopath, err := temporaryBuildDir()
-		if err != nil {
-			log.Fatal(err)
-		}
-		fmt.Println(gopath)
-
 	default:
 		log.Fatalf("Unknown command %q", cmd)
 	}
@@ -336,61 +321,38 @@ func runCommand(cmd string, target target) {
 func parseFlags() {
 	flag.StringVar(&goarch, "goarch", runtime.GOARCH, "GOARCH")
 	flag.StringVar(&goos, "goos", runtime.GOOS, "GOOS")
+	flag.StringVar(&goCmd, "gocmd", "go", "Specify `go` command")
 	flag.BoolVar(&noupgrade, "no-upgrade", noupgrade, "Disable upgrade functionality")
 	flag.StringVar(&version, "version", getVersion(), "Set compiled in version string")
 	flag.BoolVar(&race, "race", race, "Use race detector")
-	flag.BoolVar(&noBuildGopath, "no-build-gopath", noBuildGopath, "Don't build GOPATH, assume it's OK")
 	flag.StringVar(&extraTags, "tags", extraTags, "Extra tags, space separated")
 	flag.StringVar(&installSuffix, "installsuffix", installSuffix, "Install suffix, optional")
+	flag.StringVar(&pkgdir, "pkgdir", "", "Set -pkgdir parameter for `go build`")
+	flag.StringVar(&cc, "cc", os.Getenv("CC"), "Set CC environment variable for `go build`")
+	flag.BoolVar(&debugBinary, "debug-binary", debugBinary, "Create unoptimized binary to use with delve, set -gcflags='-N -l' and omit -ldflags")
 	flag.Parse()
 }

-func setup() {
-	packages := []string{
-		"github.com/alecthomas/gometalinter",
-		"github.com/AlekSi/gocov-xml",
-		"github.com/axw/gocov/gocov",
-		"github.com/FiloSottile/gvt",
-		"github.com/golang/lint/golint",
-		"github.com/gordonklaus/ineffassign",
-		"github.com/mdempsky/unconvert",
-		"github.com/mitchellh/go-wordwrap",
-		"github.com/opennota/check/cmd/...",
-		"github.com/tsenart/deadcode",
-		"golang.org/x/net/html",
-		"golang.org/x/tools/cmd/cover",
-		"honnef.co/go/simple/cmd/gosimple",
-		"honnef.co/go/staticcheck/cmd/staticcheck",
-		"honnef.co/go/unused/cmd/unused",
-	}
-	for _, pkg := range packages {
-		fmt.Println(pkg)
-		runPrint("go", "get", "-u", pkg)
-	}
-
-	runPrint("go", "install", "-v", "github.com/syncthing/syncthing/vendor/github.com/gogo/protobuf/protoc-gen-gogofast")
-}
-
 func test(pkgs ...string) {
 	lazyRebuildAssets()

 	useRace := runtime.GOARCH == "amd64"
 	switch runtime.GOOS {
-	case "darwin", "linux", "freebsd", "windows":
+	case "darwin", "linux", "freebsd": // , "windows": # See https://github.com/golang/go/issues/27089
 	default:
 		useRace = false
 	}

 	if useRace {
-		runPrint("go", append([]string{"test", "-short", "-race", "-timeout", "60s", "-tags", "purego"}, pkgs...)...)
+		runPrint(goCmd, append([]string{"test", "-short", "-race", "-timeout", timeout, "-tags", "purego"}, pkgs...)...)
 	} else {
-		runPrint("go", append([]string{"test", "-short", "-timeout", "60s", "-tags", "purego"}, pkgs...)...)
+		runPrint(goCmd, append([]string{"test", "-short", "-timeout", timeout, "-tags", "purego"}, pkgs...)...)
 	}
 }

 func bench(pkgs ...string) {
 	lazyRebuildAssets()
-	runPrint("go", append([]string{"test", "-run", "NONE", "-bench", "."}, pkgs...)...)
+	runPrint(goCmd, append([]string{"test", "-run", "NONE", "-bench", "."}, pkgs...)...)
 }

 func install(target target, tags []string) {
@@ -403,21 +365,26 @@ func install(target target, tags []string) {
 		log.Fatal(err)
 	}
 	os.Setenv("GOBIN", filepath.Join(cwd, "bin"))
-	args := []string{"install", "-v", "-ldflags", ldflags()}
-	if len(tags) > 0 {
-		args = append(args, "-tags", strings.Join(tags, " "))
-	}
-	if installSuffix != "" {
-		args = append(args, "-installsuffix", installSuffix)
-	}
-	if race {
-		args = append(args, "-race")
-	}
-	args = append(args, target.buildPkg)
+
+	args := []string{"install", "-v"}
+	args = appendParameters(args, tags, target)

 	os.Setenv("GOOS", goos)
 	os.Setenv("GOARCH", goarch)
-	runPrint("go", args...)
+	os.Setenv("CC", cc)
+
+	// On Windows generate a special file which the Go compiler will
+	// automatically use when generating Windows binaries to set things like
+	// the file icon, version, etc.
+	if goos == "windows" {
+		sysoPath, err := shouldBuildSyso(cwd)
+		if err != nil {
+			log.Printf("Warning: Windows binaries will not have file information encoded: %v", err)
+		}
+		defer shouldCleanupSyso(sysoPath)
+	}
+
+	runPrint(goCmd, args...)
 }

 func build(target target, tags []string) {
@@ -426,7 +393,36 @@ func build(target target, tags []string) {
 	tags = append(target.tags, tags...)

 	rmr(target.BinaryName())
-	args := []string{"build", "-i", "-v", "-ldflags", ldflags()}
+
+	args := []string{"build", "-v"}
+	args = appendParameters(args, tags, target)
+
+	os.Setenv("GOOS", goos)
+	os.Setenv("GOARCH", goarch)
+	os.Setenv("CC", cc)
+
+	// On Windows generate a special file which the Go compiler will
+	// automatically use when generating Windows binaries to set things like
+	// the file icon, version, etc.
+	if goos == "windows" {
+		cwd, err := os.Getwd()
+		if err != nil {
+			log.Fatal(err)
+		}
+		sysoPath, err := shouldBuildSyso(cwd)
+		if err != nil {
+			log.Printf("Warning: Windows binaries will not have file information encoded: %v", err)
+		}
+		defer shouldCleanupSyso(sysoPath)
+	}
+
+	runPrint(goCmd, args...)
+}
+
+func appendParameters(args []string, tags []string, target target) []string {
+	if pkgdir != "" {
+		args = append(args, "-pkgdir", pkgdir)
+	}
 	if len(tags) > 0 {
 		args = append(args, "-tags", strings.Join(tags, " "))
 	}
@@ -436,11 +432,19 @@ func build(target target, tags []string) {
 	if race {
 		args = append(args, "-race")
 	}
-	args = append(args, target.buildPkg)

-	os.Setenv("GOOS", goos)
-	os.Setenv("GOARCH", goarch)
-	runPrint("go", args...)
+	if !debugBinary {
+		// Regular binaries get version tagged and skip some debug symbols
+		args = append(args, "-ldflags", ldflags())
+	} else {
+		// -gcflags to disable optimizations and inlining. Skip -ldflags
+		// because `Could not launch program: decoding dwarf section info at
+		// offset 0x0: too short` on 'dlv exec ...' see
+		// https://github.com/derekparker/delve/issues/79
+		args = append(args, "-gcflags", "-N -l")
+	}
+
+	return append(args, target.buildPkg)
 }

 func buildTar(target target) {
@@ -481,6 +485,10 @@ func buildZip(target target) {

 	build(target, tags)

+	if goos == "windows" {
+		windowsCodesign(target.BinaryName())
+	}
+
 	for i := range target.archiveFiles {
 		target.archiveFiles[i].src = strings.Replace(target.archiveFiles[i].src, "{{binary}}", target.BinaryName(), 1)
 		target.archiveFiles[i].dst = strings.Replace(target.archiveFiles[i].dst, "{{binary}}", target.BinaryName(), 1)
@@ -565,6 +573,8 @@ func buildSnap(target target) {
 	snaparch := goarch
 	if snaparch == "armhf" {
 		goarch = "arm"
+	} else if snaparch == "i386" {
+		goarch = "386"
 	}
 	snapver := version
 	if strings.HasPrefix(snapver, "v") {
@@ -575,9 +585,10 @@ func buildSnap(target target) {
 		snapgrade = "stable"
 	}
 	err = tmpl.Execute(f, map[string]string{
-		"Version":      snapver,
-		"Architecture": snaparch,
-		"Grade":        snapgrade,
+		"Version":            snapver,
+		"HostArchitecture":   runtime.GOARCH,
+		"TargetArchitecture": snaparch,
+		"Grade":              snapgrade,
 	})
 	if err != nil {
 		log.Fatal(err)
@@ -587,6 +598,56 @@ func buildSnap(target target) {
 	runPrint("snapcraft")
 }

+func shouldBuildSyso(dir string) (string, error) {
+	jsonPath := filepath.Join(dir, "versioninfo.json")
+	file, err := os.Create(filepath.Join(dir, "versioninfo.json"))
+	if err != nil {
+		return "", errors.New("failed to create " + jsonPath + ": " + err.Error())
+	}
+
+	major, minor, patch, build := semanticVersion()
+	fmt.Fprintf(file, `{
+    "FixedFileInfo": {
+        "FileVersion": {
+            "Major": %s,
+            "Minor": %s,
+            "Patch": %s,
+            "Build": %s
+        }
+    },
+    "StringFileInfo": {
+        "FileDescription": "Open Source Continuous File Synchronization",
+        "LegalCopyright": "The Syncthing Authors",
+        "ProductVersion": "%s",
+        "ProductName": "Syncthing"
+    },
+    "IconPath": "assets/logo.ico"
+}`, major, minor, patch, build, getVersion())
+	file.Close()
+	defer func() {
+		if err := os.Remove(jsonPath); err != nil {
+			log.Printf("Warning: unable to remove generated %s: %v. Please remove it manually.", jsonPath, err)
+		}
+	}()
+
+	sysoPath := filepath.Join(dir, "cmd", "syncthing", "resource.syso")
+
+	if _, err := runError("goversioninfo", "-o", sysoPath); err != nil {
+		return "", errors.New("failed to create " + sysoPath + ": " + err.Error())
+	}
+
+	return sysoPath, nil
+}
+
+func shouldCleanupSyso(sysoFilePath string) {
+	if sysoFilePath == "" {
+		return
+	}
+	if err := os.Remove(sysoFilePath); err != nil {
+		log.Printf("Warning: unable to remove generated %s: %v. Please remove it manually.", sysoFilePath, err)
+	}
+}
+
 // copyFile copies a file from src to dst, ensuring the containing directory
 // exists. The permission bits are copied as well. If dst already exists and
 // the contents are identical to src the modification time is not updated.
@@ -634,12 +695,12 @@ func listFiles(dir string) []string {
 }

 func rebuildAssets() {
-	runPipe("lib/auto/gui.files.go", "go", "run", "script/genassets.go", "gui")
-	runPipe("cmd/strelaypoolsrv/auto/gui.go", "go", "run", "script/genassets.go", "cmd/strelaypoolsrv/gui")
+	os.Setenv("SOURCE_DATE_EPOCH", fmt.Sprint(buildStamp()))
+	runPrint(goCmd, "generate", "github.com/syncthing/syncthing/lib/auto", "github.com/syncthing/syncthing/cmd/strelaypoolsrv/auto")
 }

 func lazyRebuildAssets() {
-	if shouldRebuildAssets("lib/auto/gui.files.go", "gui") || shouldRebuildAssets("cmd/strelaypoolsrv/auto/gui.go", "cmd/strelaypoolsrv/auto/gui") {
+	if shouldRebuildAssets("lib/auto/gui.files.go", "gui") || shouldRebuildAssets("cmd/strelaypoolsrv/auto/gui.files.go", "cmd/strelaypoolsrv/auto/gui") {
 		rebuildAssets()
 	}
 }
@@ -671,12 +732,21 @@ func shouldRebuildAssets(target, srcdir string) bool {
 }

 func proto() {
-	runPrint("go", "generate", "github.com/syncthing/syncthing/lib/...")
+	runPrint(goCmd, "get", fmt.Sprintf("github.com/gogo/protobuf/protoc-gen-gogofast@%v", gogoProtoVersion))
+	os.MkdirAll("repos", 0755)
+	for _, dep := range dependencyRepos {
+		path := filepath.Join("repos", dep.path)
+		if _, err := os.Stat(path); err != nil {
+			runPrintInDir("repos", "git", "clone", dep.repo, dep.path)
+			runPrintInDir(path, "git", "checkout", dep.commit)
+		}
+	}
+	runPrint(goCmd, "generate", "github.com/syncthing/syncthing/lib/...", "github.com/syncthing/syncthing/cmd/stdiscosrv")
 }

 func translate() {
 	os.Chdir("gui/default/assets/lang")
-	runPipe("lang-en-new.json", "go", "run", "../../../../script/translate.go", "lang-en.json", "../../../")
+	runPipe("lang-en-new.json", goCmd, "run", "../../../../script/translate.go", "lang-en.json", "../../../")
 	os.Remove("lang-en.json")
 	err := os.Rename("lang-en-new.json", "lang-en.json")
 	if err != nil {
@@ -687,12 +757,7 @@ func translate() {

 func transifex() {
 	os.Chdir("gui/default/assets/lang")
-	runPrint("go", "run", "../../../../script/transifexdl.go")
-}
-
-func clean() {
-	rmr("bin")
-	rmr(filepath.Join(os.Getenv("GOPATH"), fmt.Sprintf("pkg/%s_%s/github.com/syncthing", goos, goarch)))
+	runPrint(goCmd, "run", "../../../../script/transifexdl.go")
 }

 func ldflags() string {
@@ -703,10 +768,10 @@ func ldflags() string {

 	b := new(bytes.Buffer)
 	b.WriteString("-w")
-	fmt.Fprintf(b, " -X main.Version%c%s", sep, version)
-	fmt.Fprintf(b, " -X main.BuildStamp%c%d", sep, buildStamp())
-	fmt.Fprintf(b, " -X main.BuildUser%c%s", sep, buildUser())
-	fmt.Fprintf(b, " -X main.BuildHost%c%s", sep, buildHost())
+	fmt.Fprintf(b, " -X github.com/syncthing/syncthing/lib/build.Version%c%s", sep, version)
+	fmt.Fprintf(b, " -X github.com/syncthing/syncthing/lib/build.Stamp%c%d", sep, buildStamp())
+	fmt.Fprintf(b, " -X github.com/syncthing/syncthing/lib/build.User%c%s", sep, buildUser())
+	fmt.Fprintf(b, " -X github.com/syncthing/syncthing/lib/build.Host%c%s", sep, buildHost())
 	return b.String()
 }

@@ -763,6 +828,15 @@ func getVersion() string {
 	return "unknown-dev"
 }

+func semanticVersion() (major, minor, patch, build string) {
+	r := regexp.MustCompile(`v(?P<Major>\d+)\.(?P<Minor>\d+).(?P<Patch>\d+).*\+(?P<CommitsAhead>\d+)`)
+	matches := r.FindStringSubmatch(getVersion())
+	if len(matches) != 5 {
+		return "0", "0", "0", "0"
+	}
+	return matches[1], matches[2], matches[3], matches[4]
+}
+
 func getBranchSuffix() string {
 	bs, err := runError("git", "branch", "-a", "--contains")
 	if err != nil {
@@ -857,7 +931,7 @@ func buildHost() string {
 func buildArch() string {
 	os := goos
 	if os == "darwin" {
-		os = "macosx"
+		os = "macos"
 	}
 	return fmt.Sprintf("%s-%s", os, goarch)
 }
@@ -880,6 +954,10 @@ func runError(cmd string, args ...string) ([]byte, error) {
 }

 func runPrint(cmd string, args ...string) {
+	runPrintInDir(".", cmd, args...)
+}
+
+func runPrintInDir(dir string, cmd string, args ...string) {
 	if debug {
 		t0 := time.Now()
 		log.Println("runPrint:", cmd, strings.Join(args, " "))
@@ -890,6 +968,7 @@ func runPrint(cmd string, args ...string) {
 	ecmd := exec.Command(cmd, args...)
 	ecmd.Stdout = os.Stdout
 	ecmd.Stderr = os.Stderr
+	ecmd.Dir = dir
 	err := ecmd.Run()
 	if err != nil {
 		log.Fatal(err)
@@ -1070,14 +1149,51 @@ func macosCodesign(file string) {
 	}
 }

+func windowsCodesign(file string) {
+	st := "signtool.exe"
+
+	if path := os.Getenv("CODESIGN_SIGNTOOL"); path != "" {
+		st = path
+	}
+
+	for i, algo := range []string{"sha1", "sha256"} {
+		args := []string{"sign", "/fd", algo}
+		if f := os.Getenv("CODESIGN_CERTIFICATE_FILE"); f != "" {
+			args = append(args, "/f", f)
+		}
+		if p := os.Getenv("CODESIGN_CERTIFICATE_PASSWORD"); p != "" {
+			args = append(args, "/p", p)
+		}
+		if tr := os.Getenv("CODESIGN_TIMESTAMP_SERVER"); tr != "" {
+			switch algo {
+			case "sha256":
+				args = append(args, "/tr", tr, "/td", algo)
+			default:
+				args = append(args, "/t", tr)
+			}
+		}
+		if i > 0 {
+			args = append(args, "/as")
+		}
+		args = append(args, file)
+
+		bs, err := runError(st, args...)
+		if err != nil {
+			log.Println("Codesign: signing failed:", string(bs))
+			return
+		}
+		log.Println("Codesign: successfully signed", file, "using", algo)
+	}
+}
+
 func metalint() {
 	lazyRebuildAssets()
-	runPrint("go", "test", "-run", "Metalint", "./meta")
+	runPrint(goCmd, "test", "-run", "Metalint", "./meta")
 }

 func metalintShort() {
 	lazyRebuildAssets()
-	runPrint("go", "test", "-short", "-run", "Metalint", "./meta")
+	runPrint(goCmd, "test", "-short", "-run", "Metalint", "./meta")
 }

 func temporaryBuildDir() (string, error) {
@@ -1106,90 +1222,6 @@ func temporaryBuildDir() (string, error) {
 	return filepath.Join(tmpDir, base), nil
 }

-func buildGOPATH(gopath string) error {
-	pkg := filepath.Join(gopath, "src/github.com/syncthing/syncthing")
-	dirs := []string{"cmd", "lib", "meta", "script", "test", "vendor"}
-
-	if debug {
-		t0 := time.Now()
-		log.Println("build temporary GOPATH in", gopath)
-		defer func() {
-			log.Println("... in", time.Since(t0))
-		}()
-	}
-
-	// Walk the sources and copy the files into the temporary GOPATH.
-	// Remember which files are supposed to be present so we can clean
-	// out everything else in the next step. The copyFile() step will
-	// only actually copy the file if it doesn't exist or the contents
-	// differ.
-
-	exists := map[string]struct{}{}
-	for _, dir := range dirs {
-		err := filepath.Walk(dir, func(path string, info os.FileInfo, err error) error {
-			if err != nil {
-				return err
-			}
-			if info.IsDir() {
-				return nil
-			}
-
-			dst := filepath.Join(pkg, path)
-			exists[dst] = struct{}{}
-
-			if err := copyFile(path, dst, info.Mode()); err != nil {
-				return err
-			}
-
-			return nil
-		})
-		if err != nil {
-			return err
-		}
-	}
-
-	// Walk the temporary GOPATH and remove any files that we wouldn't
-	// have copied there in the previous step.
-
-	filepath.Walk(pkg, func(path string, info os.FileInfo, err error) error {
-		if err != nil {
-			return err
-		}
-		if info.IsDir() {
-			return nil
-		}
-		if _, ok := exists[path]; !ok {
-			os.Remove(path)
-		}
-		return nil
-	})
-
-	return nil
-}
-
-func gopath() string {
-	if gopath := os.Getenv("GOPATH"); gopath != "" {
-		// The env var is set, use that.
-		return gopath
-	}
-
-	// Ask Go what it thinks.
-	bs, err := runError("go", "env", "GOPATH")
-	if err != nil {
-		return ""
-	}
-
-	// We got something. Check if we are in fact available in that location.
-	gopath := string(bs)
-	if _, err := os.Stat(filepath.Join(gopath, "src/github.com/syncthing/syncthing/build.go")); err == nil {
-		// That seems to be the gopath.
-		return gopath
-	}
-
-	// The gopath is not valid.
-	return ""
-}
-
 func (t target) BinaryName() string {
 	if goos == "windows" {
 		return t.binaryName + ".exe"
--- a/build.sh
+++ b/build.sh
@@ -48,9 +48,6 @@ case "${1:-default}" in
 		;;

 	test)
-		ulimit -t 600 &>/dev/null || true
-		ulimit -d 512000 &>/dev/null || true
-		ulimit -m 512000 &>/dev/null || true
 		LOGGER_DISCARD=1 build test
 		;;

@@ -62,8 +59,8 @@ case "${1:-default}" in
 		go run script/authors.go
 		build transifex
 		pushd man ; ./refresh.sh ; popd
-		git add -A gui man
-		git commit -m 'gui, man: Update docs & translations'
+		git add -A gui man AUTHORS
+		git commit -m 'gui, man, authors: Update docs, translations, and contributors'
 		;;

 	noupgrade)
@@ -94,9 +91,6 @@ case "${1:-default}" in
 		;;

 	test-xunit)
-		ulimit -t 600 &>/dev/null || true
-		ulimit -d 512000 &>/dev/null || true
-		ulimit -m 512000 &>/dev/null || true

 		(GOPATH="$(pwd)/Godeps/_workspace:$GOPATH" go test -v -race ./lib/... ./cmd/... || true) > tests.out
 		go2xunit -output tests.xml -fail < tests.out
--- a/cmd/stbench/main.go
+++ b/cmd/stbench/main.go
@@ -92,7 +92,7 @@ loop:
 	return t1.Sub(t0)
 }

-// report stops the given process and reports on it's resource usage in two
+// report stops the given process and reports on its resource usage in two
 // ways: human readable to stderr, and CSV to stdout.
 func report(p *rc.Process, wallTime time.Duration) {
 	sv, err := p.SystemVersion()
--- a/cmd/stcli/LICENSE
+++ b/cmd/stcli/LICENSE
@@ -1,19 +0,0 @@
-Copyright (C) 2014 Audrius Butkevičius
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-of the Software, and to permit persons to whom the Software is furnished to do
-so, subject to the following conditions:
-
- The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
--- a/cmd/stcli/client.go
+++ b/cmd/stcli/client.go
@@ -1,115 +1,95 @@
-// Copyright (C) 2014 Audrius Butkevičius
+// Copyright (C) 2019 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.

 package main

 import (
 	"bytes"
+	"context"
 	"crypto/tls"
+	"fmt"
+	"net"
 	"net/http"
 	"strings"

-	"github.com/AudriusButkevicius/cli"
+	"github.com/syncthing/syncthing/lib/config"
 )

 type APIClient struct {
-	httpClient http.Client
-	endpoint   string
-	apikey     string
-	username   string
-	password   string
-	id         string
-	csrf       string
+	http.Client
+	cfg    config.GUIConfiguration
+	apikey string
 }

-var instance *APIClient
-
-func getClient(c *cli.Context) *APIClient {
-	if instance != nil {
-		return instance
-	}
-	endpoint := c.GlobalString("endpoint")
-	if !strings.HasPrefix(endpoint, "http") {
-		endpoint = "http://" + endpoint
-	}
+func getClient(cfg config.GUIConfiguration) *APIClient {
 	httpClient := http.Client{
 		Transport: &http.Transport{
 			TLSClientConfig: &tls.Config{
-				InsecureSkipVerify: c.GlobalBool("insecure"),
+				InsecureSkipVerify: true,
+			},
+			DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
+				return net.Dial(cfg.Network(), cfg.Address())
 			},
 		},
 	}
-	client := APIClient{
-		httpClient: httpClient,
-		endpoint:   endpoint,
-		apikey:     c.GlobalString("apikey"),
-		username:   c.GlobalString("username"),
-		password:   c.GlobalString("password"),
+	return &APIClient{
+		Client: httpClient,
+		cfg:    cfg,
+		apikey: cfg.APIKey,
 	}
-
-	if client.apikey == "" {
-		request, err := http.NewRequest("GET", client.endpoint, nil)
-		die(err)
-		response := client.handleRequest(request)
-		client.id = response.Header.Get("X-Syncthing-ID")
-		if client.id == "" {
-			die("Failed to get device ID")
-		}
-		for _, item := range response.Cookies() {
-			if item.Name == "CSRF-Token-"+client.id[:5] {
-				client.csrf = item.Value
-				goto csrffound
-			}
-		}
-		die("Failed to get CSRF token")
-	csrffound:
-	}
-	instance = &client
-	return &client
 }

-func (client *APIClient) handleRequest(request *http.Request) *http.Response {
-	if client.apikey != "" {
-		request.Header.Set("X-API-Key", client.apikey)
+func (c *APIClient) Endpoint() string {
+	if c.cfg.Network() == "unix" {
+		return "http://unix/"
 	}
-	if client.username != "" || client.password != "" {
-		request.SetBasicAuth(client.username, client.password)
-	}
-	if client.csrf != "" {
-		request.Header.Set("X-CSRF-Token-"+client.id[:5], client.csrf)
+	url := c.cfg.URL()
+	if !strings.HasSuffix(url, "/") {
+		url += "/"
 	}
+	return url
+}

-	response, err := client.httpClient.Do(request)
-	die(err)
+func (c *APIClient) Do(req *http.Request) (*http.Response, error) {
+	req.Header.Set("X-API-Key", c.apikey)
+	resp, err := c.Client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	return resp, checkResponse(resp)
+}

+func (c *APIClient) Get(url string) (*http.Response, error) {
+	request, err := http.NewRequest("GET", c.Endpoint()+"rest/"+url, nil)
+	if err != nil {
+		return nil, err
+	}
+	return c.Do(request)
+}
+
+func (c *APIClient) Post(url, body string) (*http.Response, error) {
+	request, err := http.NewRequest("POST", c.Endpoint()+"rest/"+url, bytes.NewBufferString(body))
+	if err != nil {
+		return nil, err
+	}
+	return c.Do(request)
+}
+
+func checkResponse(response *http.Response) error {
 	if response.StatusCode == 404 {
-		die("Invalid endpoint or API call")
-	} else if response.StatusCode == 401 {
-		die("Invalid username or password")
+		return fmt.Errorf("Invalid endpoint or API call")
 	} else if response.StatusCode == 403 {
-		if client.apikey == "" {
-			die("Invalid CSRF token")
-		}
-		die("Invalid API key")
+		return fmt.Errorf("Invalid API key")
 	} else if response.StatusCode != 200 {
-		body := strings.TrimSpace(string(responseToBArray(response)))
-		if body != "" {
-			die(body)
+		data, err := responseToBArray(response)
+		if err != nil {
+			return err
 		}
-		die("Unknown HTTP status returned: " + response.Status)
+		body := strings.TrimSpace(string(data))
+		return fmt.Errorf("Unexpected HTTP status returned: %s\n%s", response.Status, body)
 	}
-	return response
-}
-
-func httpGet(c *cli.Context, url string) *http.Response {
-	client := getClient(c)
-	request, err := http.NewRequest("GET", client.endpoint+"/rest/"+url, nil)
-	die(err)
-	return client.handleRequest(request)
-}
-
-func httpPost(c *cli.Context, url string, body string) *http.Response {
-	client := getClient(c)
-	request, err := http.NewRequest("POST", client.endpoint+"/rest/"+url, bytes.NewBufferString(body))
-	die(err)
-	return client.handleRequest(request)
+	return nil
 }
--- a/cmd/stcli/cmd_devices.go
+++ b/cmd/stcli/cmd_devices.go
@@ -1,188 +0,0 @@
-// Copyright (C) 2014 Audrius Butkevičius
-
-package main
-
-import (
-	"fmt"
-	"strings"
-
-	"github.com/AudriusButkevicius/cli"
-	"github.com/syncthing/syncthing/lib/config"
-)
-
-func init() {
-	cliCommands = append(cliCommands, cli.Command{
-		Name:     "devices",
-		HideHelp: true,
-		Usage:    "Device command group",
-		Subcommands: []cli.Command{
-			{
-				Name:     "list",
-				Usage:    "List registered devices",
-				Requires: &cli.Requires{},
-				Action:   devicesList,
-			},
-			{
-				Name:     "add",
-				Usage:    "Add a new device",
-				Requires: &cli.Requires{"device id", "device name?"},
-				Action:   devicesAdd,
-			},
-			{
-				Name:     "remove",
-				Usage:    "Remove an existing device",
-				Requires: &cli.Requires{"device id"},
-				Action:   devicesRemove,
-			},
-			{
-				Name:     "get",
-				Usage:    "Get a property of a device",
-				Requires: &cli.Requires{"device id", "property"},
-				Action:   devicesGet,
-			},
-			{
-				Name:     "set",
-				Usage:    "Set a property of a device",
-				Requires: &cli.Requires{"device id", "property", "value..."},
-				Action:   devicesSet,
-			},
-		},
-	})
-}
-
-func devicesList(c *cli.Context) {
-	cfg := getConfig(c)
-	first := true
-	writer := newTableWriter()
-	for _, device := range cfg.Devices {
-		if !first {
-			fmt.Fprintln(writer)
-		}
-		fmt.Fprintln(writer, "ID:\t", device.DeviceID, "\t")
-		fmt.Fprintln(writer, "Name:\t", device.Name, "\t(name)")
-		fmt.Fprintln(writer, "Address:\t", strings.Join(device.Addresses, " "), "\t(address)")
-		fmt.Fprintln(writer, "Compression:\t", device.Compression, "\t(compression)")
-		fmt.Fprintln(writer, "Certificate name:\t", device.CertName, "\t(certname)")
-		fmt.Fprintln(writer, "Introducer:\t", device.Introducer, "\t(introducer)")
-		first = false
-	}
-	writer.Flush()
-}
-
-func devicesAdd(c *cli.Context) {
-	nid := c.Args()[0]
-	id := parseDeviceID(nid)
-
-	newDevice := config.DeviceConfiguration{
-		DeviceID:  id,
-		Name:      nid,
-		Addresses: []string{"dynamic"},
-	}
-
-	if len(c.Args()) > 1 {
-		newDevice.Name = c.Args()[1]
-	}
-
-	if len(c.Args()) > 2 {
-		addresses := c.Args()[2:]
-		for _, item := range addresses {
-			if item == "dynamic" {
-				continue
-			}
-			validAddress(item)
-		}
-		newDevice.Addresses = addresses
-	}
-
-	cfg := getConfig(c)
-	for _, device := range cfg.Devices {
-		if device.DeviceID == id {
-			die("Device " + nid + " already exists")
-		}
-	}
-	cfg.Devices = append(cfg.Devices, newDevice)
-	setConfig(c, cfg)
-}
-
-func devicesRemove(c *cli.Context) {
-	nid := c.Args()[0]
-	id := parseDeviceID(nid)
-	if nid == getMyID(c) {
-		die("Cannot remove yourself")
-	}
-	cfg := getConfig(c)
-	for i, device := range cfg.Devices {
-		if device.DeviceID == id {
-			last := len(cfg.Devices) - 1
-			cfg.Devices[i] = cfg.Devices[last]
-			cfg.Devices = cfg.Devices[:last]
-			setConfig(c, cfg)
-			return
-		}
-	}
-	die("Device " + nid + " not found")
-}
-
-func devicesGet(c *cli.Context) {
-	nid := c.Args()[0]
-	id := parseDeviceID(nid)
-	arg := c.Args()[1]
-	cfg := getConfig(c)
-	for _, device := range cfg.Devices {
-		if device.DeviceID != id {
-			continue
-		}
-		switch strings.ToLower(arg) {
-		case "name":
-			fmt.Println(device.Name)
-		case "address":
-			fmt.Println(strings.Join(device.Addresses, "\n"))
-		case "compression":
-			fmt.Println(device.Compression.String())
-		case "certname":
-			fmt.Println(device.CertName)
-		case "introducer":
-			fmt.Println(device.Introducer)
-		default:
-			die("Invalid property: " + arg + "\nAvailable properties: name, address, compression, certname, introducer")
-		}
-		return
-	}
-	die("Device " + nid + " not found")
-}
-
-func devicesSet(c *cli.Context) {
-	nid := c.Args()[0]
-	id := parseDeviceID(nid)
-	arg := c.Args()[1]
-	config := getConfig(c)
-	for i, device := range config.Devices {
-		if device.DeviceID != id {
-			continue
-		}
-		switch strings.ToLower(arg) {
-		case "name":
-			config.Devices[i].Name = strings.Join(c.Args()[2:], " ")
-		case "address":
-			for _, item := range c.Args()[2:] {
-				if item == "dynamic" {
-					continue
-				}
-				validAddress(item)
-			}
-			config.Devices[i].Addresses = c.Args()[2:]
-		case "compression":
-			err := config.Devices[i].Compression.UnmarshalText([]byte(c.Args()[2]))
-			die(err)
-		case "certname":
-			config.Devices[i].CertName = strings.Join(c.Args()[2:], " ")
-		case "introducer":
-			config.Devices[i].Introducer = parseBool(c.Args()[2])
-		default:
-			die("Invalid property: " + arg + "\nAvailable properties: name, address, compression, certname, introducer")
-		}
-		setConfig(c, config)
-		return
-	}
-	die("Device " + nid + " not found")
-}
--- a/cmd/stcli/cmd_errors.go
+++ b/cmd/stcli/cmd_errors.go
@@ -1,67 +0,0 @@
-// Copyright (C) 2014 Audrius Butkevičius
-
-package main
-
-import (
-	"encoding/json"
-	"fmt"
-	"strings"
-
-	"github.com/AudriusButkevicius/cli"
-)
-
-func init() {
-	cliCommands = append(cliCommands, cli.Command{
-		Name:     "errors",
-		HideHelp: true,
-		Usage:    "Error command group",
-		Subcommands: []cli.Command{
-			{
-				Name:     "show",
-				Usage:    "Show pending errors",
-				Requires: &cli.Requires{},
-				Action:   errorsShow,
-			},
-			{
-				Name:     "push",
-				Usage:    "Push an error to active clients",
-				Requires: &cli.Requires{"error message..."},
-				Action:   errorsPush,
-			},
-			{
-				Name:     "clear",
-				Usage:    "Clear pending errors",
-				Requires: &cli.Requires{},
-				Action:   wrappedHTTPPost("system/error/clear"),
-			},
-		},
-	})
-}
-
-func errorsShow(c *cli.Context) {
-	response := httpGet(c, "system/error")
-	var data map[string][]map[string]interface{}
-	json.Unmarshal(responseToBArray(response), &data)
-	writer := newTableWriter()
-	for _, item := range data["errors"] {
-		time := item["time"].(string)[:19]
-		time = strings.Replace(time, "T", " ", 1)
-		err := item["error"].(string)
-		err = strings.TrimSpace(err)
-		fmt.Fprintln(writer, time+":\t"+err)
-	}
-	writer.Flush()
-}
-
-func errorsPush(c *cli.Context) {
-	err := strings.Join(c.Args(), " ")
-	response := httpPost(c, "system/error", strings.TrimSpace(err))
-	if response.StatusCode != 200 {
-		err = fmt.Sprint("Failed to push error\nStatus code: ", response.StatusCode)
-		body := string(responseToBArray(response))
-		if body != "" {
-			err += "\nBody: " + body
-		}
-		die(err)
-	}
-}
--- a/cmd/stcli/cmd_folders.go
+++ b/cmd/stcli/cmd_folders.go
@@ -1,351 +0,0 @@
-// Copyright (C) 2014 Audrius Butkevičius
-
-package main
-
-import (
-	"fmt"
-	"path/filepath"
-	"strings"
-
-	"github.com/AudriusButkevicius/cli"
-	"github.com/syncthing/syncthing/lib/config"
-)
-
-func init() {
-	cliCommands = append(cliCommands, cli.Command{
-		Name:     "folders",
-		HideHelp: true,
-		Usage:    "Folder command group",
-		Subcommands: []cli.Command{
-			{
-				Name:     "list",
-				Usage:    "List available folders",
-				Requires: &cli.Requires{},
-				Action:   foldersList,
-			},
-			{
-				Name:     "add",
-				Usage:    "Add a new folder",
-				Requires: &cli.Requires{"folder id", "directory"},
-				Action:   foldersAdd,
-			},
-			{
-				Name:     "remove",
-				Usage:    "Remove an existing folder",
-				Requires: &cli.Requires{"folder id"},
-				Action:   foldersRemove,
-			},
-			{
-				Name:     "override",
-				Usage:    "Override changes from other nodes for a master folder",
-				Requires: &cli.Requires{"folder id"},
-				Action:   foldersOverride,
-			},
-			{
-				Name:     "get",
-				Usage:    "Get a property of a folder",
-				Requires: &cli.Requires{"folder id", "property"},
-				Action:   foldersGet,
-			},
-			{
-				Name:     "set",
-				Usage:    "Set a property of a folder",
-				Requires: &cli.Requires{"folder id", "property", "value..."},
-				Action:   foldersSet,
-			},
-			{
-				Name:     "unset",
-				Usage:    "Unset a property of a folder",
-				Requires: &cli.Requires{"folder id", "property"},
-				Action:   foldersUnset,
-			},
-			{
-				Name:     "devices",
-				Usage:    "Folder devices command group",
-				HideHelp: true,
-				Subcommands: []cli.Command{
-					{
-						Name:     "list",
-						Usage:    "List of devices which the folder is shared with",
-						Requires: &cli.Requires{"folder id"},
-						Action:   foldersDevicesList,
-					},
-					{
-						Name:     "add",
-						Usage:    "Share a folder with a device",
-						Requires: &cli.Requires{"folder id", "device id"},
-						Action:   foldersDevicesAdd,
-					},
-					{
-						Name:     "remove",
-						Usage:    "Unshare a folder with a device",
-						Requires: &cli.Requires{"folder id", "device id"},
-						Action:   foldersDevicesRemove,
-					},
-					{
-						Name:     "clear",
-						Usage:    "Unshare a folder with all devices",
-						Requires: &cli.Requires{"folder id"},
-						Action:   foldersDevicesClear,
-					},
-				},
-			},
-		},
-	})
-}
-
-func foldersList(c *cli.Context) {
-	cfg := getConfig(c)
-	first := true
-	writer := newTableWriter()
-	for _, folder := range cfg.Folders {
-		if !first {
-			fmt.Fprintln(writer)
-		}
-		fmt.Fprintln(writer, "ID:\t", folder.ID, "\t")
-		fmt.Fprintln(writer, "Path:\t", folder.RawPath, "\t(directory)")
-		fmt.Fprintln(writer, "Folder type:\t", folder.Type, "\t(type)")
-		fmt.Fprintln(writer, "Ignore permissions:\t", folder.IgnorePerms, "\t(permissions)")
-		fmt.Fprintln(writer, "Rescan interval in seconds:\t", folder.RescanIntervalS, "\t(rescan)")
-
-		if folder.Versioning.Type != "" {
-			fmt.Fprintln(writer, "Versioning:\t", folder.Versioning.Type, "\t(versioning)")
-			for key, value := range folder.Versioning.Params {
-				fmt.Fprintf(writer, "Versioning %s:\t %s \t(versioning-%s)\n", key, value, key)
-			}
-		}
-		first = false
-	}
-	writer.Flush()
-}
-
-func foldersAdd(c *cli.Context) {
-	cfg := getConfig(c)
-	abs, err := filepath.Abs(c.Args()[1])
-	die(err)
-	folder := config.FolderConfiguration{
-		ID:      c.Args()[0],
-		RawPath: filepath.Clean(abs),
-	}
-	cfg.Folders = append(cfg.Folders, folder)
-	setConfig(c, cfg)
-}
-
-func foldersRemove(c *cli.Context) {
-	cfg := getConfig(c)
-	rid := c.Args()[0]
-	for i, folder := range cfg.Folders {
-		if folder.ID == rid {
-			last := len(cfg.Folders) - 1
-			cfg.Folders[i] = cfg.Folders[last]
-			cfg.Folders = cfg.Folders[:last]
-			setConfig(c, cfg)
-			return
-		}
-	}
-	die("Folder " + rid + " not found")
-}
-
-func foldersOverride(c *cli.Context) {
-	cfg := getConfig(c)
-	rid := c.Args()[0]
-	for _, folder := range cfg.Folders {
-		if folder.ID == rid && folder.Type == config.FolderTypeSendOnly {
-			response := httpPost(c, "db/override", "")
-			if response.StatusCode != 200 {
-				err := fmt.Sprint("Failed to override changes\nStatus code: ", response.StatusCode)
-				body := string(responseToBArray(response))
-				if body != "" {
-					err += "\nBody: " + body
-				}
-				die(err)
-			}
-			return
-		}
-	}
-	die("Folder " + rid + " not found or folder not master")
-}
-
-func foldersGet(c *cli.Context) {
-	cfg := getConfig(c)
-	rid := c.Args()[0]
-	arg := strings.ToLower(c.Args()[1])
-	for _, folder := range cfg.Folders {
-		if folder.ID != rid {
-			continue
-		}
-		if strings.HasPrefix(arg, "versioning-") {
-			arg = arg[11:]
-			value, ok := folder.Versioning.Params[arg]
-			if ok {
-				fmt.Println(value)
-				return
-			}
-			die("Versioning property " + c.Args()[1][11:] + " not found")
-		}
-		switch arg {
-		case "directory":
-			fmt.Println(folder.RawPath)
-		case "type":
-			fmt.Println(folder.Type)
-		case "permissions":
-			fmt.Println(folder.IgnorePerms)
-		case "rescan":
-			fmt.Println(folder.RescanIntervalS)
-		case "versioning":
-			if folder.Versioning.Type != "" {
-				fmt.Println(folder.Versioning.Type)
-			}
-		default:
-			die("Invalid property: " + c.Args()[1] + "\nAvailable properties: directory, type, permissions, versioning, versioning-<key>")
-		}
-		return
-	}
-	die("Folder " + rid + " not found")
-}
-
-func foldersSet(c *cli.Context) {
-	rid := c.Args()[0]
-	arg := strings.ToLower(c.Args()[1])
-	val := strings.Join(c.Args()[2:], " ")
-	cfg := getConfig(c)
-	for i, folder := range cfg.Folders {
-		if folder.ID != rid {
-			continue
-		}
-		if strings.HasPrefix(arg, "versioning-") {
-			cfg.Folders[i].Versioning.Params[arg[11:]] = val
-			setConfig(c, cfg)
-			return
-		}
-		switch arg {
-		case "directory":
-			cfg.Folders[i].RawPath = val
-		case "type":
-			var t config.FolderType
-			if err := t.UnmarshalText([]byte(val)); err != nil {
-				die("Invalid folder type: " + err.Error())
-			}
-			cfg.Folders[i].Type = t
-		case "permissions":
-			cfg.Folders[i].IgnorePerms = parseBool(val)
-		case "rescan":
-			cfg.Folders[i].RescanIntervalS = parseInt(val)
-		case "versioning":
-			cfg.Folders[i].Versioning.Type = val
-		default:
-			die("Invalid property: " + c.Args()[1] + "\nAvailable properties: directory, master, permissions, versioning, versioning-<key>")
-		}
-		setConfig(c, cfg)
-		return
-	}
-	die("Folder " + rid + " not found")
-}
-
-func foldersUnset(c *cli.Context) {
-	rid := c.Args()[0]
-	arg := strings.ToLower(c.Args()[1])
-	cfg := getConfig(c)
-	for i, folder := range cfg.Folders {
-		if folder.ID != rid {
-			continue
-		}
-		if strings.HasPrefix(arg, "versioning-") {
-			arg = arg[11:]
-			if _, ok := folder.Versioning.Params[arg]; ok {
-				delete(cfg.Folders[i].Versioning.Params, arg)
-				setConfig(c, cfg)
-				return
-			}
-			die("Versioning property " + c.Args()[1][11:] + " not found")
-		}
-		switch arg {
-		case "versioning":
-			cfg.Folders[i].Versioning.Type = ""
-			cfg.Folders[i].Versioning.Params = make(map[string]string)
-		default:
-			die("Invalid property: " + c.Args()[1] + "\nAvailable properties: versioning, versioning-<key>")
-		}
-		setConfig(c, cfg)
-		return
-	}
-	die("Folder " + rid + " not found")
-}
-
-func foldersDevicesList(c *cli.Context) {
-	rid := c.Args()[0]
-	cfg := getConfig(c)
-	for _, folder := range cfg.Folders {
-		if folder.ID != rid {
-			continue
-		}
-		for _, device := range folder.Devices {
-			fmt.Println(device.DeviceID)
-		}
-		return
-	}
-	die("Folder " + rid + " not found")
-}
-
-func foldersDevicesAdd(c *cli.Context) {
-	rid := c.Args()[0]
-	nid := parseDeviceID(c.Args()[1])
-	cfg := getConfig(c)
-	for i, folder := range cfg.Folders {
-		if folder.ID != rid {
-			continue
-		}
-		for _, device := range folder.Devices {
-			if device.DeviceID == nid {
-				die("Device " + c.Args()[1] + " is already part of this folder")
-			}
-		}
-		for _, device := range cfg.Devices {
-			if device.DeviceID == nid {
-				cfg.Folders[i].Devices = append(folder.Devices, config.FolderDeviceConfiguration{
-					DeviceID: device.DeviceID,
-				})
-				setConfig(c, cfg)
-				return
-			}
-		}
-		die("Device " + c.Args()[1] + " not found in device list")
-	}
-	die("Folder " + rid + " not found")
-}
-
-func foldersDevicesRemove(c *cli.Context) {
-	rid := c.Args()[0]
-	nid := parseDeviceID(c.Args()[1])
-	cfg := getConfig(c)
-	for ri, folder := range cfg.Folders {
-		if folder.ID != rid {
-			continue
-		}
-		for ni, device := range folder.Devices {
-			if device.DeviceID == nid {
-				last := len(folder.Devices) - 1
-				cfg.Folders[ri].Devices[ni] = folder.Devices[last]
-				cfg.Folders[ri].Devices = cfg.Folders[ri].Devices[:last]
-				setConfig(c, cfg)
-				return
-			}
-		}
-		die("Device " + c.Args()[1] + " not found")
-	}
-	die("Folder " + rid + " not found")
-}
-
-func foldersDevicesClear(c *cli.Context) {
-	rid := c.Args()[0]
-	cfg := getConfig(c)
-	for i, folder := range cfg.Folders {
-		if folder.ID != rid {
-			continue
-		}
-		cfg.Folders[i].Devices = []config.FolderDeviceConfiguration{}
-		setConfig(c, cfg)
-		return
-	}
-	die("Folder " + rid + " not found")
-}
--- a/cmd/stcli/cmd_general.go
+++ b/cmd/stcli/cmd_general.go
@@ -1,78 +0,0 @@
-// Copyright (C) 2014 Audrius Butkevičius
-
-package main
-
-import (
-	"encoding/json"
-	"fmt"
-
-	"github.com/AudriusButkevicius/cli"
-)
-
-func init() {
-	cliCommands = append(cliCommands, []cli.Command{
-		{
-			Name:     "id",
-			Usage:    "Get ID of the Syncthing client",
-			Requires: &cli.Requires{},
-			Action:   generalID,
-		},
-		{
-			Name:     "status",
-			Usage:    "Configuration status, whether or not a restart is required for changes to take effect",
-			Requires: &cli.Requires{},
-			Action:   generalStatus,
-		},
-		{
-			Name:     "restart",
-			Usage:    "Restart syncthing",
-			Requires: &cli.Requires{},
-			Action:   wrappedHTTPPost("system/restart"),
-		},
-		{
-			Name:     "shutdown",
-			Usage:    "Shutdown syncthing",
-			Requires: &cli.Requires{},
-			Action:   wrappedHTTPPost("system/shutdown"),
-		},
-		{
-			Name:     "reset",
-			Usage:    "Reset syncthing deleting all folders and devices",
-			Requires: &cli.Requires{},
-			Action:   wrappedHTTPPost("system/reset"),
-		},
-		{
-			Name:     "upgrade",
-			Usage:    "Upgrade syncthing (if a newer version is available)",
-			Requires: &cli.Requires{},
-			Action:   wrappedHTTPPost("system/upgrade"),
-		},
-		{
-			Name:     "version",
-			Usage:    "Syncthing client version",
-			Requires: &cli.Requires{},
-			Action:   generalVersion,
-		},
-	}...)
-}
-
-func generalID(c *cli.Context) {
-	fmt.Println(getMyID(c))
-}
-
-func generalStatus(c *cli.Context) {
-	response := httpGet(c, "system/config/insync")
-	var status struct{ ConfigInSync bool }
-	json.Unmarshal(responseToBArray(response), &status)
-	if !status.ConfigInSync {
-		die("Config out of sync")
-	}
-	fmt.Println("Config in sync")
-}
-
-func generalVersion(c *cli.Context) {
-	response := httpGet(c, "system/version")
-	version := make(map[string]interface{})
-	json.Unmarshal(responseToBArray(response), &version)
-	prettyPrintJSON(version)
-}
--- a/cmd/stcli/cmd_gui.go
+++ b/cmd/stcli/cmd_gui.go
@@ -1,127 +0,0 @@
-// Copyright (C) 2014 Audrius Butkevičius
-
-package main
-
-import (
-	"fmt"
-	"strings"
-
-	"github.com/AudriusButkevicius/cli"
-)
-
-func init() {
-	cliCommands = append(cliCommands, cli.Command{
-		Name:     "gui",
-		HideHelp: true,
-		Usage:    "GUI command group",
-		Subcommands: []cli.Command{
-			{
-				Name:     "dump",
-				Usage:    "Show all GUI configuration settings",
-				Requires: &cli.Requires{},
-				Action:   guiDump,
-			},
-			{
-				Name:     "get",
-				Usage:    "Get a GUI configuration setting",
-				Requires: &cli.Requires{"setting"},
-				Action:   guiGet,
-			},
-			{
-				Name:     "set",
-				Usage:    "Set a GUI configuration setting",
-				Requires: &cli.Requires{"setting", "value"},
-				Action:   guiSet,
-			},
-			{
-				Name:     "unset",
-				Usage:    "Unset a GUI configuration setting",
-				Requires: &cli.Requires{"setting"},
-				Action:   guiUnset,
-			},
-		},
-	})
-}
-
-func guiDump(c *cli.Context) {
-	cfg := getConfig(c).GUI
-	writer := newTableWriter()
-	fmt.Fprintln(writer, "Enabled:\t", cfg.Enabled, "\t(enabled)")
-	fmt.Fprintln(writer, "Use HTTPS:\t", cfg.UseTLS(), "\t(tls)")
-	fmt.Fprintln(writer, "Listen Addresses:\t", cfg.Address(), "\t(address)")
-	if cfg.User != "" {
-		fmt.Fprintln(writer, "Authentication User:\t", cfg.User, "\t(username)")
-		fmt.Fprintln(writer, "Authentication Password:\t", cfg.Password, "\t(password)")
-	}
-	if cfg.APIKey != "" {
-		fmt.Fprintln(writer, "API Key:\t", cfg.APIKey, "\t(apikey)")
-	}
-	writer.Flush()
-}
-
-func guiGet(c *cli.Context) {
-	cfg := getConfig(c).GUI
-	arg := c.Args()[0]
-	switch strings.ToLower(arg) {
-	case "enabled":
-		fmt.Println(cfg.Enabled)
-	case "tls":
-		fmt.Println(cfg.UseTLS())
-	case "address":
-		fmt.Println(cfg.Address())
-	case "user":
-		if cfg.User != "" {
-			fmt.Println(cfg.User)
-		}
-	case "password":
-		if cfg.User != "" {
-			fmt.Println(cfg.Password)
-		}
-	case "apikey":
-		if cfg.APIKey != "" {
-			fmt.Println(cfg.APIKey)
-		}
-	default:
-		die("Invalid setting: " + arg + "\nAvailable settings: enabled, tls, address, user, password, apikey")
-	}
-}
-
-func guiSet(c *cli.Context) {
-	cfg := getConfig(c)
-	arg := c.Args()[0]
-	val := c.Args()[1]
-	switch strings.ToLower(arg) {
-	case "enabled":
-		cfg.GUI.Enabled = parseBool(val)
-	case "tls":
-		cfg.GUI.RawUseTLS = parseBool(val)
-	case "address":
-		validAddress(val)
-		cfg.GUI.RawAddress = val
-	case "user":
-		cfg.GUI.User = val
-	case "password":
-		cfg.GUI.Password = val
-	case "apikey":
-		cfg.GUI.APIKey = val
-	default:
-		die("Invalid setting: " + arg + "\nAvailable settings: enabled, tls, address, user, password, apikey")
-	}
-	setConfig(c, cfg)
-}
-
-func guiUnset(c *cli.Context) {
-	cfg := getConfig(c)
-	arg := c.Args()[0]
-	switch strings.ToLower(arg) {
-	case "user":
-		cfg.GUI.User = ""
-	case "password":
-		cfg.GUI.Password = ""
-	case "apikey":
-		cfg.GUI.APIKey = ""
-	default:
-		die("Invalid setting: " + arg + "\nAvailable settings: user, password, apikey")
-	}
-	setConfig(c, cfg)
-}
--- a/cmd/stcli/cmd_options.go
+++ b/cmd/stcli/cmd_options.go
@@ -1,173 +0,0 @@
-// Copyright (C) 2014 Audrius Butkevičius
-
-package main
-
-import (
-	"fmt"
-	"strings"
-
-	"github.com/AudriusButkevicius/cli"
-)
-
-func init() {
-	cliCommands = append(cliCommands, cli.Command{
-		Name:     "options",
-		HideHelp: true,
-		Usage:    "Options command group",
-		Subcommands: []cli.Command{
-			{
-				Name:     "dump",
-				Usage:    "Show all Syncthing option settings",
-				Requires: &cli.Requires{},
-				Action:   optionsDump,
-			},
-			{
-				Name:     "get",
-				Usage:    "Get a Syncthing option setting",
-				Requires: &cli.Requires{"setting"},
-				Action:   optionsGet,
-			},
-			{
-				Name:     "set",
-				Usage:    "Set a Syncthing option setting",
-				Requires: &cli.Requires{"setting", "value..."},
-				Action:   optionsSet,
-			},
-		},
-	})
-}
-
-func optionsDump(c *cli.Context) {
-	cfg := getConfig(c).Options
-	writer := newTableWriter()
-
-	fmt.Fprintln(writer, "Sync protocol listen addresses:\t", strings.Join(cfg.ListenAddresses, " "), "\t(addresses)")
-	fmt.Fprintln(writer, "Global discovery enabled:\t", cfg.GlobalAnnEnabled, "\t(globalannenabled)")
-	fmt.Fprintln(writer, "Global discovery servers:\t", strings.Join(cfg.GlobalAnnServers, " "), "\t(globalannserver)")
-
-	fmt.Fprintln(writer, "Local discovery enabled:\t", cfg.LocalAnnEnabled, "\t(localannenabled)")
-	fmt.Fprintln(writer, "Local discovery port:\t", cfg.LocalAnnPort, "\t(localannport)")
-
-	fmt.Fprintln(writer, "Outgoing rate limit in KiB/s:\t", cfg.MaxSendKbps, "\t(maxsend)")
-	fmt.Fprintln(writer, "Incoming rate limit in KiB/s:\t", cfg.MaxRecvKbps, "\t(maxrecv)")
-	fmt.Fprintln(writer, "Reconnect interval in seconds:\t", cfg.ReconnectIntervalS, "\t(reconnect)")
-	fmt.Fprintln(writer, "Start browser:\t", cfg.StartBrowser, "\t(browser)")
-	fmt.Fprintln(writer, "Enable UPnP:\t", cfg.NATEnabled, "\t(nat)")
-	fmt.Fprintln(writer, "UPnP Lease in minutes:\t", cfg.NATLeaseM, "\t(natlease)")
-	fmt.Fprintln(writer, "UPnP Renewal period in minutes:\t", cfg.NATRenewalM, "\t(natrenew)")
-	fmt.Fprintln(writer, "Restart on Wake Up:\t", cfg.RestartOnWakeup, "\t(wake)")
-
-	reporting := "unrecognized value"
-	switch cfg.URAccepted {
-	case -1:
-		reporting = "false"
-	case 0:
-		reporting = "undecided/false"
-	case 1:
-		reporting = "true"
-	}
-	fmt.Fprintln(writer, "Anonymous usage reporting:\t", reporting, "\t(reporting)")
-
-	writer.Flush()
-}
-
-func optionsGet(c *cli.Context) {
-	cfg := getConfig(c).Options
-	arg := c.Args()[0]
-	switch strings.ToLower(arg) {
-	case "address":
-		fmt.Println(strings.Join(cfg.ListenAddresses, "\n"))
-	case "globalannenabled":
-		fmt.Println(cfg.GlobalAnnEnabled)
-	case "globalannservers":
-		fmt.Println(strings.Join(cfg.GlobalAnnServers, "\n"))
-	case "localannenabled":
-		fmt.Println(cfg.LocalAnnEnabled)
-	case "localannport":
-		fmt.Println(cfg.LocalAnnPort)
-	case "maxsend":
-		fmt.Println(cfg.MaxSendKbps)
-	case "maxrecv":
-		fmt.Println(cfg.MaxRecvKbps)
-	case "reconnect":
-		fmt.Println(cfg.ReconnectIntervalS)
-	case "browser":
-		fmt.Println(cfg.StartBrowser)
-	case "nat":
-		fmt.Println(cfg.NATEnabled)
-	case "natlease":
-		fmt.Println(cfg.NATLeaseM)
-	case "natrenew":
-		fmt.Println(cfg.NATRenewalM)
-	case "reporting":
-		switch cfg.URAccepted {
-		case -1:
-			fmt.Println("false")
-		case 0:
-			fmt.Println("undecided/false")
-		case 1:
-			fmt.Println("true")
-		default:
-			fmt.Println("unknown")
-		}
-	case "wake":
-		fmt.Println(cfg.RestartOnWakeup)
-	default:
-		die("Invalid setting: " + arg + "\nAvailable settings: address, globalannenabled, globalannserver, localannenabled, localannport, maxsend, maxrecv, reconnect, browser, upnp, upnplease, upnprenew, reporting, wake")
-	}
-}
-
-func optionsSet(c *cli.Context) {
-	config := getConfig(c)
-	arg := c.Args()[0]
-	val := c.Args()[1]
-	switch strings.ToLower(arg) {
-	case "address":
-		for _, item := range c.Args().Tail() {
-			validAddress(item)
-		}
-		config.Options.ListenAddresses = c.Args().Tail()
-	case "globalannenabled":
-		config.Options.GlobalAnnEnabled = parseBool(val)
-	case "globalannserver":
-		for _, item := range c.Args().Tail() {
-			validAddress(item)
-		}
-		config.Options.GlobalAnnServers = c.Args().Tail()
-	case "localannenabled":
-		config.Options.LocalAnnEnabled = parseBool(val)
-	case "localannport":
-		config.Options.LocalAnnPort = parsePort(val)
-	case "maxsend":
-		config.Options.MaxSendKbps = parseUint(val)
-	case "maxrecv":
-		config.Options.MaxRecvKbps = parseUint(val)
-	case "reconnect":
-		config.Options.ReconnectIntervalS = parseUint(val)
-	case "browser":
-		config.Options.StartBrowser = parseBool(val)
-	case "nat":
-		config.Options.NATEnabled = parseBool(val)
-	case "natlease":
-		config.Options.NATLeaseM = parseUint(val)
-	case "natrenew":
-		config.Options.NATRenewalM = parseUint(val)
-	case "reporting":
-		switch strings.ToLower(val) {
-		case "u", "undecided", "unset":
-			config.Options.URAccepted = 0
-		default:
-			boolvalue := parseBool(val)
-			if boolvalue {
-				config.Options.URAccepted = 1
-			} else {
-				config.Options.URAccepted = -1
-			}
-		}
-	case "wake":
-		config.Options.RestartOnWakeup = parseBool(val)
-	default:
-		die("Invalid setting: " + arg + "\nAvailable settings: address, globalannenabled, globalannserver, localannenabled, localannport, maxsend, maxrecv, reconnect, browser, upnp, upnplease, upnprenew, reporting, wake")
-	}
-	setConfig(c, config)
-}
--- a/cmd/stcli/cmd_report.go
+++ b/cmd/stcli/cmd_report.go
@@ -1,72 +0,0 @@
-// Copyright (C) 2014 Audrius Butkevičius
-
-package main
-
-import (
-	"encoding/json"
-	"fmt"
-
-	"github.com/AudriusButkevicius/cli"
-)
-
-func init() {
-	cliCommands = append(cliCommands, cli.Command{
-		Name:     "report",
-		HideHelp: true,
-		Usage:    "Reporting command group",
-		Subcommands: []cli.Command{
-			{
-				Name:     "system",
-				Usage:    "Report system state",
-				Requires: &cli.Requires{},
-				Action:   reportSystem,
-			},
-			{
-				Name:     "connections",
-				Usage:    "Report about connections to other devices",
-				Requires: &cli.Requires{},
-				Action:   reportConnections,
-			},
-			{
-				Name:     "usage",
-				Usage:    "Usage report",
-				Requires: &cli.Requires{},
-				Action:   reportUsage,
-			},
-		},
-	})
-}
-
-func reportSystem(c *cli.Context) {
-	response := httpGet(c, "system/status")
-	data := make(map[string]interface{})
-	json.Unmarshal(responseToBArray(response), &data)
-	prettyPrintJSON(data)
-}
-
-func reportConnections(c *cli.Context) {
-	response := httpGet(c, "system/connections")
-	data := make(map[string]map[string]interface{})
-	json.Unmarshal(responseToBArray(response), &data)
-	var overall map[string]interface{}
-	for key, value := range data {
-		if key == "total" {
-			overall = value
-			continue
-		}
-		value["Device ID"] = key
-		prettyPrintJSON(value)
-		fmt.Println()
-	}
-	if overall != nil {
-		fmt.Println("=== Overall statistics ===")
-		prettyPrintJSON(overall)
-	}
-}
-
-func reportUsage(c *cli.Context) {
-	response := httpGet(c, "svc/report")
-	report := make(map[string]interface{})
-	json.Unmarshal(responseToBArray(response), &report)
-	prettyPrintJSON(report)
-}
--- a/cmd/stcli/errors.go
+++ b/cmd/stcli/errors.go
@@ -0,0 +1,60 @@
+// Copyright (C) 2019 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/urfave/cli"
+)
+
+var errorsCommand = cli.Command{
+	Name:     "errors",
+	HideHelp: true,
+	Usage:    "Error command group",
+	Subcommands: []cli.Command{
+		{
+			Name:   "show",
+			Usage:  "Show pending errors",
+			Action: expects(0, dumpOutput("system/error")),
+		},
+		{
+			Name:      "push",
+			Usage:     "Push an error to active clients",
+			ArgsUsage: "[error message]",
+			Action:    expects(1, errorsPush),
+		},
+		{
+			Name:   "clear",
+			Usage:  "Clear pending errors",
+			Action: expects(0, emptyPost("system/error/clear")),
+		},
+	},
+}
+
+func errorsPush(c *cli.Context) error {
+	client := c.App.Metadata["client"].(*APIClient)
+	errStr := strings.Join(c.Args(), " ")
+	response, err := client.Post("system/error", strings.TrimSpace(errStr))
+	if err != nil {
+		return err
+	}
+	if response.StatusCode != 200 {
+		errStr = fmt.Sprint("Failed to push error\nStatus code: ", response.StatusCode)
+		bytes, err := responseToBArray(response)
+		if err != nil {
+			return err
+		}
+		body := string(bytes)
+		if body != "" {
+			errStr += "\nBody: " + body
+		}
+		return fmt.Errorf(errStr)
+	}
+	return nil
+}
--- a/cmd/stcli/labels.go
+++ b/cmd/stcli/labels.go
@@ -1,31 +0,0 @@
-// Copyright (C) 2014 Audrius Butkevičius
-
-package main
-
-var jsonAttributeLabels = map[string]string{
-	"folderMaxMiB":   "Largest folder size in MiB",
-	"folderMaxFiles": "Largest folder file count",
-	"longVersion":    "Long version",
-	"totMiB":         "Total size in MiB",
-	"totFiles":       "Total files",
-	"uniqueID":       "Unique ID",
-	"numFolders":     "Folder count",
-	"numDevices":     "Device count",
-	"memoryUsageMiB": "Memory usage in MiB",
-	"memorySize":     "Total memory in MiB",
-	"sha256Perf":     "SHA256 Benchmark",
-	"At":             "Last contacted",
-	"Completion":     "Percent complete",
-	"InBytesTotal":   "Total bytes received",
-	"OutBytesTotal":  "Total bytes sent",
-	"ClientVersion":  "Client version",
-	"alloc":          "Memory allocated in bytes",
-	"sys":            "Memory using in bytes",
-	"cpuPercent":     "CPU load in percent",
-	"extAnnounceOK":  "External announcments working",
-	"goroutines":     "Number of Go routines",
-	"myID":           "Client ID",
-	"tilde":          "Tilde expands to",
-	"arch":           "Architecture",
-	"os":             "OS",
-}
--- a/cmd/stcli/main.go
+++ b/cmd/stcli/main.go
@@ -1,63 +1,192 @@
-// Copyright (C) 2014 Audrius Butkevičius
+// Copyright (C) 2019 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.

 package main

 import (
-	"sort"
+	"bufio"
+	"crypto/tls"
+	"encoding/json"
+	"flag"
+	"log"
+	"os"
+	"reflect"
+	"strings"

-	"github.com/AudriusButkevicius/cli"
+	"github.com/AudriusButkevicius/recli"
+	"github.com/flynn-archive/go-shlex"
+	"github.com/mattn/go-isatty"
+	"github.com/pkg/errors"
+	"github.com/syncthing/syncthing/lib/build"
+	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/locations"
+	"github.com/syncthing/syncthing/lib/protocol"
+	"github.com/urfave/cli"
 )

-type ByAlphabet []cli.Command
-
-func (a ByAlphabet) Len() int           { return len(a) }
-func (a ByAlphabet) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
-func (a ByAlphabet) Less(i, j int) bool { return a[i].Name < a[j].Name }
-
-var cliCommands []cli.Command
-
 func main() {
-	app := cli.NewApp()
-	app.Name = "syncthing-cli"
-	app.Author = "Audrius Butkevičius"
-	app.Email = "audrius.butkevicius@gmail.com"
-	app.Usage = "Syncthing command line interface"
-	app.Version = "0.1"
-	app.HideHelp = true
+	// This is somewhat a hack around a chicken and egg problem.
+	// We need to set the home directory and potentially other flags to know where the syncthing instance is running
+	// in order to get it's config ... which we then use to construct the actual CLI ... at which point it's too late
+	// to add flags there...
+	homeBaseDir := locations.GetBaseDir(locations.ConfigBaseDir)
+	guiCfg := config.GUIConfiguration{}

-	app.Flags = []cli.Flag{
+	flags := flag.NewFlagSet("", flag.ContinueOnError)
+	flags.StringVar(&guiCfg.RawAddress, "gui-address", guiCfg.RawAddress, "Override GUI address (e.g. \"http://192.0.2.42:8443\")")
+	flags.StringVar(&guiCfg.APIKey, "gui-apikey", guiCfg.APIKey, "Override GUI API key")
+	flags.StringVar(&homeBaseDir, "home", homeBaseDir, "Set configuration directory")
+
+	// Implement the same flags at the lower CLI, with the same default values (pre-parse), but do nothing with them.
+	// This is so that we could reuse os.Args
+	fakeFlags := []cli.Flag{
 		cli.StringFlag{
-			Name:   "endpoint, e",
-			Value:  "http://127.0.0.1:8384",
-			Usage:  "End point to connect to",
-			EnvVar: "STENDPOINT",
+			Name:  "gui-address",
+			Value: guiCfg.RawAddress,
+			Usage: "Override GUI address (e.g. \"http://192.0.2.42:8443\")",
 		},
 		cli.StringFlag{
-			Name:   "apikey, k",
-			Value:  "",
-			Usage:  "API Key",
-			EnvVar: "STAPIKEY",
+			Name:  "gui-apikey",
+			Value: guiCfg.APIKey,
+			Usage: "Override GUI API key",
 		},
 		cli.StringFlag{
-			Name:   "username, u",
-			Value:  "",
-			Usage:  "Username",
-			EnvVar: "STUSERNAME",
-		},
-		cli.StringFlag{
-			Name:   "password, p",
-			Value:  "",
-			Usage:  "Password",
-			EnvVar: "STPASSWORD",
-		},
-		cli.BoolFlag{
-			Name:   "insecure, i",
-			Usage:  "Do not verify SSL certificate",
-			EnvVar: "STINSECURE",
+			Name:  "home",
+			Value: homeBaseDir,
+			Usage: "Set configuration directory",
 		},
 	}

-	sort.Sort(ByAlphabet(cliCommands))
-	app.Commands = cliCommands
-	app.RunAndExitOnError()
+	// Do not print usage of these flags, and ignore errors as this can't understand plenty of things
+	flags.Usage = func() {}
+	_ = flags.Parse(os.Args[1:])
+
+	// Now if the API key and address is not provided (we are not connecting to a remote instance),
+	// try to rip it out of the config.
+	if guiCfg.RawAddress == "" && guiCfg.APIKey == "" {
+		// Update the base directory
+		err := locations.SetBaseDir(locations.ConfigBaseDir, homeBaseDir)
+		if err != nil {
+			log.Fatal(errors.Wrap(err, "setting home"))
+		}
+
+		// Load the certs and get the ID
+		cert, err := tls.LoadX509KeyPair(
+			locations.Get(locations.CertFile),
+			locations.Get(locations.KeyFile),
+		)
+		if err != nil {
+			log.Fatal(errors.Wrap(err, "reading device ID"))
+		}
+
+		myID := protocol.NewDeviceID(cert.Certificate[0])
+
+		// Load the config
+		cfg, err := config.Load(locations.Get(locations.ConfigFile), myID)
+		if err != nil {
+			log.Fatalln(errors.Wrap(err, "loading config"))
+		}
+
+		guiCfg = cfg.GUI()
+	} else if guiCfg.Address() == "" || guiCfg.APIKey == "" {
+		log.Fatalln("Both -gui-address and -gui-apikey should be specified")
+	}
+
+	if guiCfg.Address() == "" {
+		log.Fatalln("Could not find GUI Address")
+	}
+
+	if guiCfg.APIKey == "" {
+		log.Fatalln("Could not find GUI API key")
+	}
+
+	client := getClient(guiCfg)
+
+	cfg, err := getConfig(client)
+	original := cfg.Copy()
+	if err != nil {
+		log.Fatalln(errors.Wrap(err, "getting config"))
+	}
+
+	// Copy the config and set the default flags
+	recliCfg := recli.DefaultConfig
+	recliCfg.IDTag.Name = "xml"
+	recliCfg.SkipTag.Name = "json"
+
+	commands, err := recli.New(recliCfg).Construct(&cfg)
+	if err != nil {
+		log.Fatalln(errors.Wrap(err, "config reflect"))
+	}
+
+	// Construct the actual CLI
+	app := cli.NewApp()
+	app.Name = "stcli"
+	app.HelpName = app.Name
+	app.Author = "The Syncthing Authors"
+	app.Usage = "Syncthing command line interface"
+	app.Version = strings.Replace(build.LongVersion, "syncthing", app.Name, 1)
+	app.Flags = fakeFlags
+	app.Metadata = map[string]interface{}{
+		"client": client,
+	}
+	app.Commands = []cli.Command{
+		{
+			Name:        "config",
+			HideHelp:    true,
+			Usage:       "Configuration modification command group",
+			Subcommands: commands,
+		},
+		showCommand,
+		operationCommand,
+		errorsCommand,
+	}
+
+	tty := isatty.IsTerminal(os.Stdin.Fd()) || isatty.IsCygwinTerminal(os.Stdin.Fd())
+	if !tty {
+		// Not a TTY, consume from stdin
+		scanner := bufio.NewScanner(os.Stdin)
+		for scanner.Scan() {
+			input, err := shlex.Split(scanner.Text())
+			if err != nil {
+				log.Fatalln(errors.Wrap(err, "parsing input"))
+			}
+			if len(input) == 0 {
+				continue
+			}
+			err = app.Run(append(os.Args, input...))
+			if err != nil {
+				log.Fatalln(err)
+			}
+		}
+		err = scanner.Err()
+		if err != nil {
+			log.Fatalln(err)
+		}
+	} else {
+		err = app.Run(os.Args)
+		if err != nil {
+			log.Fatalln(err)
+		}
+	}
+
+	if !reflect.DeepEqual(cfg, original) {
+		body, err := json.MarshalIndent(cfg, "", "  ")
+		if err != nil {
+			log.Fatalln(err)
+		}
+		resp, err := client.Post("system/config", string(body))
+		if err != nil {
+			log.Fatalln(err)
+		}
+		if resp.StatusCode != 200 {
+			body, err := responseToBArray(resp)
+			if err != nil {
+				log.Fatalln(err)
+			}
+			log.Fatalln(string(body))
+		}
+	}
 }
--- a/cmd/stcli/operations.go
+++ b/cmd/stcli/operations.go
@@ -0,0 +1,78 @@
+// Copyright (C) 2019 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"fmt"
+
+	"github.com/urfave/cli"
+)
+
+var operationCommand = cli.Command{
+	Name:     "operations",
+	HideHelp: true,
+	Usage:    "Operation command group",
+	Subcommands: []cli.Command{
+		{
+			Name:   "restart",
+			Usage:  "Restart syncthing",
+			Action: expects(0, emptyPost("system/restart")),
+		},
+		{
+			Name:   "shutdown",
+			Usage:  "Shutdown syncthing",
+			Action: expects(0, emptyPost("system/shutdown")),
+		},
+		{
+			Name:   "reset",
+			Usage:  "Reset syncthing deleting all folders and devices",
+			Action: expects(0, emptyPost("system/reset")),
+		},
+		{
+			Name:   "upgrade",
+			Usage:  "Upgrade syncthing (if a newer version is available)",
+			Action: expects(0, emptyPost("system/upgrade")),
+		},
+		{
+			Name:      "folder-override",
+			Usage:     "Override changes on folder (remote for sendonly, local for receiveonly)",
+			ArgsUsage: "[folder id]",
+			Action:    expects(1, foldersOverride),
+		},
+	},
+}
+
+func foldersOverride(c *cli.Context) error {
+	client := c.App.Metadata["client"].(*APIClient)
+	cfg, err := getConfig(client)
+	if err != nil {
+		return err
+	}
+	rid := c.Args()[0]
+	for _, folder := range cfg.Folders {
+		if folder.ID == rid {
+			response, err := client.Post("db/override", "")
+			if err != nil {
+				return err
+			}
+			if response.StatusCode != 200 {
+				errStr := fmt.Sprint("Failed to override changes\nStatus code: ", response.StatusCode)
+				bytes, err := responseToBArray(response)
+				if err != nil {
+					return err
+				}
+				body := string(bytes)
+				if body != "" {
+					errStr += "\nBody: " + body
+				}
+				return fmt.Errorf(errStr)
+			}
+			return nil
+		}
+	}
+	return fmt.Errorf("Folder " + rid + " not found")
+}
--- a/cmd/stcli/show.go
+++ b/cmd/stcli/show.go
@@ -0,0 +1,44 @@
+// Copyright (C) 2019 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"github.com/urfave/cli"
+)
+
+var showCommand = cli.Command{
+	Name:     "show",
+	HideHelp: true,
+	Usage:    "Show command group",
+	Subcommands: []cli.Command{
+		{
+			Name:   "version",
+			Usage:  "Show syncthing client version",
+			Action: expects(0, dumpOutput("system/version")),
+		},
+		{
+			Name:   "config-status",
+			Usage:  "Show configuration status, whether or not a restart is required for changes to take effect",
+			Action: expects(0, dumpOutput("system/config/insync")),
+		},
+		{
+			Name:   "system",
+			Usage:  "Show system status",
+			Action: expects(0, dumpOutput("system/status")),
+		},
+		{
+			Name:   "connections",
+			Usage:  "Report about connections to other devices",
+			Action: expects(0, dumpOutput("system/connections")),
+		},
+		{
+			Name:   "usage",
+			Usage:  "Show usage report",
+			Action: expects(0, dumpOutput("svc/report")),
+		},
+	},
+}
--- a/cmd/stcli/utils.go
+++ b/cmd/stcli/utils.go
@@ -1,4 +1,8 @@
-// Copyright (C) 2014 Audrius Butkevičius
+// Copyright (C) 2019 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.

 package main

@@ -8,78 +12,37 @@ import (
 	"io/ioutil"
 	"net/http"
 	"os"
-	"regexp"
-	"sort"
-	"strconv"
-	"strings"
 	"text/tabwriter"
-	"unicode"

-	"github.com/AudriusButkevicius/cli"
 	"github.com/syncthing/syncthing/lib/config"
-	"github.com/syncthing/syncthing/lib/protocol"
+	"github.com/urfave/cli"
 )

-func responseToBArray(response *http.Response) []byte {
-	defer response.Body.Close()
+func responseToBArray(response *http.Response) ([]byte, error) {
 	bytes, err := ioutil.ReadAll(response.Body)
 	if err != nil {
-		die(err)
+		return nil, err
 	}
-	return bytes
+	return bytes, response.Body.Close()
 }

-func die(vals ...interface{}) {
-	if len(vals) > 1 || vals[0] != nil {
-		os.Stderr.WriteString(fmt.Sprintln(vals...))
-		os.Exit(1)
+func emptyPost(url string) cli.ActionFunc {
+	return func(c *cli.Context) error {
+		client := c.App.Metadata["client"].(*APIClient)
+		_, err := client.Post(url, "")
+		return err
 	}
 }

-func wrappedHTTPPost(url string) func(c *cli.Context) {
-	return func(c *cli.Context) {
-		httpPost(c, url, "")
-	}
-}
-
-func prettyPrintJSON(json map[string]interface{}) {
-	writer := newTableWriter()
-	remap := make(map[string]interface{})
-	for k, v := range json {
-		key, ok := jsonAttributeLabels[k]
-		if !ok {
-			key = firstUpper(k)
+func dumpOutput(url string) cli.ActionFunc {
+	return func(c *cli.Context) error {
+		client := c.App.Metadata["client"].(*APIClient)
+		response, err := client.Get(url)
+		if err != nil {
+			return err
 		}
-		remap[key] = v
+		return prettyPrintResponse(c, response)
 	}
-
-	jsonKeys := make([]string, 0, len(remap))
-	for key := range remap {
-		jsonKeys = append(jsonKeys, key)
-	}
-	sort.Strings(jsonKeys)
-	for _, k := range jsonKeys {
-		var value string
-		rvalue := remap[k]
-		switch rvalue.(type) {
-		case int, int16, int32, int64, uint, uint16, uint32, uint64, float32, float64:
-			value = fmt.Sprintf("%.0f", rvalue)
-		default:
-			value = fmt.Sprint(rvalue)
-		}
-		if value == "" {
-			continue
-		}
-		fmt.Fprintln(writer, k+":\t"+value)
-	}
-	writer.Flush()
-}
-
-func firstUpper(str string) string {
-	for i, v := range str {
-		return string(unicode.ToUpper(v)) + str[i+1:]
-	}
-	return ""
 }

 func newTableWriter() *tabwriter.Writer {
@@ -88,78 +51,51 @@ func newTableWriter() *tabwriter.Writer {
 	return writer
 }

-func getMyID(c *cli.Context) string {
-	response := httpGet(c, "system/status")
-	data := make(map[string]interface{})
-	json.Unmarshal(responseToBArray(response), &data)
-	return data["myID"].(string)
-}
-
-func getConfig(c *cli.Context) config.Configuration {
-	response := httpGet(c, "system/config")
-	config := config.Configuration{}
-	json.Unmarshal(responseToBArray(response), &config)
-	return config
-}
-
-func setConfig(c *cli.Context, cfg config.Configuration) {
-	body, err := json.Marshal(cfg)
-	die(err)
-	response := httpPost(c, "system/config", string(body))
-	if response.StatusCode != 200 {
-		die("Unexpected status code", response.StatusCode)
-	}
-}
-
-func parseBool(input string) bool {
-	val, err := strconv.ParseBool(input)
+func getConfig(c *APIClient) (config.Configuration, error) {
+	cfg := config.Configuration{}
+	response, err := c.Get("system/config")
 	if err != nil {
-		die(input + " is not a valid value for a boolean")
+		return cfg, err
 	}
-	return val
-}
-
-func parseInt(input string) int {
-	val, err := strconv.ParseInt(input, 0, 64)
+	bytes, err := responseToBArray(response)
 	if err != nil {
-		die(input + " is not a valid value for an integer")
+		return cfg, err
 	}
-	return int(val)
+	err = json.Unmarshal(bytes, &cfg)
+	if err == nil {
+		return cfg, err
+	}
+	return cfg, nil
 }

-func parseUint(input string) int {
-	val, err := strconv.ParseUint(input, 0, 64)
+func expects(n int, actionFunc cli.ActionFunc) cli.ActionFunc {
+	return func(ctx *cli.Context) error {
+		if ctx.NArg() != n {
+			plural := ""
+			if n != 1 {
+				plural = "s"
+			}
+			return fmt.Errorf("expected %d argument%s, got %d", n, plural, ctx.NArg())
+		}
+		return actionFunc(ctx)
+	}
+}
+
+func prettyPrintJSON(data interface{}) error {
+	enc := json.NewEncoder(os.Stdout)
+	enc.SetIndent("", "  ")
+	return enc.Encode(data)
+}
+
+func prettyPrintResponse(c *cli.Context, response *http.Response) error {
+	bytes, err := responseToBArray(response)
 	if err != nil {
-		die(input + " is not a valid value for an unsigned integer")
+		return err
 	}
-	return int(val)
-}
-
-func parsePort(input string) int {
-	port := parseUint(input)
-	if port < 1 || port > 65535 {
-		die(input + " is not a valid port\nExpected value between 1 and 65535")
-	}
-	return port
-}
-
-func validAddress(input string) {
-	tokens := strings.Split(input, ":")
-	if len(tokens) != 2 {
-		die(input + " is not a valid value for an address\nExpected format <ip or hostname>:<port>")
-	}
-	matched, err := regexp.MatchString("^[a-zA-Z0-9]+([-a-zA-Z0-9.]+[-a-zA-Z0-9]+)?$", tokens[0])
-	die(err)
-	if !matched {
-		die(input + " is not a valid value for an address\nExpected format <ip or hostname>:<port>")
-	}
-	parsePort(tokens[1])
-}
-
-func parseDeviceID(input string) protocol.DeviceID {
-	device, err := protocol.DeviceIDFromString(input)
-	if err != nil {
-		die(input + " is not a valid device id")
-	}
-	return device
+	var data interface{}
+	if err := json.Unmarshal(bytes, &data); err != nil {
+		return err
+	}
+	// TODO: Check flag for pretty print format
+	return prettyPrintJSON(data)
 }
--- a/cmd/stcompdirs/main.go
+++ b/cmd/stcompdirs/main.go
@@ -88,10 +88,10 @@ func startWalker(dir string, res chan<- fileInfo, abort <-chan struct{}) chan er
 		}

 		rn, _ := filepath.Rel(dir, path)
-		if rn == "." || rn == ".stfolder" {
+		if rn == "." {
 			return nil
 		}
-		if rn == ".stversions" {
+		if rn == ".stversions" || rn == ".stfolder" {
 			return filepath.SkipDir
 		}

--- a/cmd/stdiscosrv/LICENSE
+++ b/cmd/stdiscosrv/LICENSE
@@ -1,19 +0,0 @@
-Copyright (C) 2014-2015 The Discosrv Authors
-
-Permission is hereby granted, free of charge, to any person obtaining a copy of
-this software and associated documentation files (the "Software"), to deal in
-the Software without restriction, including without limitation the rights to
-use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
-of the Software, and to permit persons to whom the Software is furnished to do
-so, subject to the following conditions:
-
- The above copyright notice and this permission notice shall be included in
-  all copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
--- a/cmd/stdiscosrv/README.md
+++ b/cmd/stdiscosrv/README.md
@@ -6,33 +6,5 @@ This is the global discovery server for the `syncthing` project.
 Usage
 -----

-The discovery server supports `ql` and `postgres` backends.
-Specify the backend via `-db-backend` and the database DSN via `-db-dsn`.
+https://docs.syncthing.net/users/stdiscosrv.html

-By default it will use in-memory `ql` backend. If you wish to persist the
-information on disk between restarts in `ql`, specify a file DSN:
-
-```bash
-$ stdiscosrv -db-dsn="file:///var/run/stdiscosrv.db"
-```
-
-For `postgres`, you will need to create a database and a user with permissions
-to create tables in it, then start the stdiscosrv as follows:
-
-```bash
-$ export STDISCOSRV_DB_DSN="postgres://user:password@localhost/databasename"
-$ stdiscosrv -db-backend="postgres"
-```
-
-You can pass the DSN as command line option, but the value what you pass in will
-be visible in most process managers, potentially exposing the database password
-to other users.
-
-In all cases, the appropriate tables and indexes will be created at first
-startup. If it doesn't exit with an error, you're fine.
-
-See `stdiscosrv -help` for other options.
-
-##### Third-party attribution
-
-[cznic/lldb](https://github.com/cznic/lldb), Copyright (C) 2014 The lldb Authors.
--- a/cmd/stdiscosrv/apisrv.go
+++ b/cmd/stdiscosrv/apisrv.go
@@ -0,0 +1,411 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"bytes"
+	"context"
+	"crypto/tls"
+	"encoding/json"
+	"encoding/pem"
+	"fmt"
+	"log"
+	"math/rand"
+	"net"
+	"net/http"
+	"net/url"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/syncthing/syncthing/lib/protocol"
+)
+
+// announcement is the format received from and sent to clients
+type announcement struct {
+	Seen      time.Time `json:"seen"`
+	Addresses []string  `json:"addresses"`
+}
+
+type apiSrv struct {
+	addr     string
+	cert     tls.Certificate
+	db       database
+	listener net.Listener
+	repl     replicator // optional
+	useHTTP  bool
+
+	mapsMut sync.Mutex
+	misses  map[string]int32
+}
+
+type requestID int64
+
+func (i requestID) String() string {
+	return fmt.Sprintf("%016x", int64(i))
+}
+
+type contextKey int
+
+const idKey contextKey = iota
+
+func newAPISrv(addr string, cert tls.Certificate, db database, repl replicator, useHTTP bool) *apiSrv {
+	return &apiSrv{
+		addr:    addr,
+		cert:    cert,
+		db:      db,
+		repl:    repl,
+		useHTTP: useHTTP,
+		misses:  make(map[string]int32),
+	}
+}
+
+func (s *apiSrv) Serve() {
+	if s.useHTTP {
+		listener, err := net.Listen("tcp", s.addr)
+		if err != nil {
+			log.Println("Listen:", err)
+			return
+		}
+		s.listener = listener
+	} else {
+		tlsCfg := &tls.Config{
+			Certificates:           []tls.Certificate{s.cert},
+			ClientAuth:             tls.RequestClientCert,
+			SessionTicketsDisabled: true,
+			MinVersion:             tls.VersionTLS12,
+			CipherSuites: []uint16{
+				tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
+				tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
+				tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+				tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+				tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+				tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+			},
+		}
+
+		tlsListener, err := tls.Listen("tcp", s.addr, tlsCfg)
+		if err != nil {
+			log.Println("Listen:", err)
+			return
+		}
+		s.listener = tlsListener
+	}
+
+	http.HandleFunc("/", s.handler)
+	http.HandleFunc("/ping", handlePing)
+
+	srv := &http.Server{
+		ReadTimeout:    httpReadTimeout,
+		WriteTimeout:   httpWriteTimeout,
+		MaxHeaderBytes: httpMaxHeaderBytes,
+	}
+
+	if err := srv.Serve(s.listener); err != nil {
+		log.Println("Serve:", err)
+	}
+}
+
+var topCtx = context.Background()
+
+func (s *apiSrv) handler(w http.ResponseWriter, req *http.Request) {
+	t0 := time.Now()
+
+	lw := NewLoggingResponseWriter(w)
+
+	defer func() {
+		diff := time.Since(t0)
+		apiRequestsSeconds.WithLabelValues(req.Method).Observe(diff.Seconds())
+		apiRequestsTotal.WithLabelValues(req.Method, strconv.Itoa(lw.statusCode)).Inc()
+	}()
+
+	reqID := requestID(rand.Int63())
+	ctx := context.WithValue(topCtx, idKey, reqID)
+
+	if debug {
+		log.Println(reqID, req.Method, req.URL)
+	}
+
+	var remoteIP net.IP
+	if s.useHTTP {
+		remoteIP = net.ParseIP(req.Header.Get("X-Forwarded-For"))
+	} else {
+		addr, err := net.ResolveTCPAddr("tcp", req.RemoteAddr)
+		if err != nil {
+			log.Println("remoteAddr:", err)
+			lw.Header().Set("Retry-After", errorRetryAfterString())
+			http.Error(lw, "Internal Server Error", http.StatusInternalServerError)
+			apiRequestsTotal.WithLabelValues("no_remote_addr").Inc()
+			return
+		}
+		remoteIP = addr.IP
+	}
+
+	switch req.Method {
+	case "GET":
+		s.handleGET(ctx, lw, req)
+	case "POST":
+		s.handlePOST(ctx, remoteIP, lw, req)
+	default:
+		http.Error(lw, "Method Not Allowed", http.StatusMethodNotAllowed)
+	}
+}
+
+func (s *apiSrv) handleGET(ctx context.Context, w http.ResponseWriter, req *http.Request) {
+	reqID := ctx.Value(idKey).(requestID)
+
+	deviceID, err := protocol.DeviceIDFromString(req.URL.Query().Get("device"))
+	if err != nil {
+		if debug {
+			log.Println(reqID, "bad device param")
+		}
+		lookupRequestsTotal.WithLabelValues("bad_request").Inc()
+		w.Header().Set("Retry-After", errorRetryAfterString())
+		http.Error(w, "Bad Request", http.StatusBadRequest)
+		return
+	}
+
+	key := deviceID.String()
+	rec, err := s.db.get(key)
+	if err != nil {
+		// some sort of internal error
+		lookupRequestsTotal.WithLabelValues("internal_error").Inc()
+		w.Header().Set("Retry-After", errorRetryAfterString())
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		return
+	}
+
+	if len(rec.Addresses) == 0 {
+		lookupRequestsTotal.WithLabelValues("not_found").Inc()
+
+		s.mapsMut.Lock()
+		misses := s.misses[key]
+		if misses < rec.Misses {
+			misses = rec.Misses + 1
+		} else {
+			misses++
+		}
+		s.misses[key] = misses
+		s.mapsMut.Unlock()
+
+		if misses%notFoundMissesWriteInterval == 0 {
+			rec.Misses = misses
+			rec.Missed = time.Now().UnixNano()
+			rec.Addresses = nil
+			// rec.Seen retained from get
+			s.db.put(key, rec)
+		}
+
+		w.Header().Set("Retry-After", notFoundRetryAfterString(int(misses)))
+		http.Error(w, "Not Found", http.StatusNotFound)
+		return
+	}
+
+	lookupRequestsTotal.WithLabelValues("success").Inc()
+
+	bs, _ := json.Marshal(announcement{
+		Seen:      time.Unix(0, rec.Seen),
+		Addresses: addressStrs(rec.Addresses),
+	})
+	w.Header().Set("Content-Type", "application/json")
+	w.Write(bs)
+}
+
+func (s *apiSrv) handlePOST(ctx context.Context, remoteIP net.IP, w http.ResponseWriter, req *http.Request) {
+	reqID := ctx.Value(idKey).(requestID)
+
+	rawCert := certificateBytes(req)
+	if rawCert == nil {
+		if debug {
+			log.Println(reqID, "no certificates")
+		}
+		announceRequestsTotal.WithLabelValues("no_certificate").Inc()
+		w.Header().Set("Retry-After", errorRetryAfterString())
+		http.Error(w, "Forbidden", http.StatusForbidden)
+		return
+	}
+
+	var ann announcement
+	if err := json.NewDecoder(req.Body).Decode(&ann); err != nil {
+		if debug {
+			log.Println(reqID, "decode:", err)
+		}
+		announceRequestsTotal.WithLabelValues("bad_request").Inc()
+		w.Header().Set("Retry-After", errorRetryAfterString())
+		http.Error(w, "Bad Request", http.StatusBadRequest)
+		return
+	}
+
+	deviceID := protocol.NewDeviceID(rawCert)
+
+	addresses := fixupAddresses(remoteIP, ann.Addresses)
+	if len(addresses) == 0 {
+		announceRequestsTotal.WithLabelValues("bad_request").Inc()
+		w.Header().Set("Retry-After", errorRetryAfterString())
+		http.Error(w, "Bad Request", http.StatusBadRequest)
+		return
+	}
+
+	if err := s.handleAnnounce(remoteIP, deviceID, addresses); err != nil {
+		announceRequestsTotal.WithLabelValues("internal_error").Inc()
+		w.Header().Set("Retry-After", errorRetryAfterString())
+		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
+		return
+	}
+
+	announceRequestsTotal.WithLabelValues("success").Inc()
+
+	w.Header().Set("Reannounce-After", reannounceAfterString())
+	w.WriteHeader(http.StatusNoContent)
+}
+
+func (s *apiSrv) Stop() {
+	s.listener.Close()
+}
+
+func (s *apiSrv) handleAnnounce(remote net.IP, deviceID protocol.DeviceID, addresses []string) error {
+	key := deviceID.String()
+	now := time.Now()
+	expire := now.Add(addressExpiryTime).UnixNano()
+
+	dbAddrs := make([]DatabaseAddress, len(addresses))
+	for i := range addresses {
+		dbAddrs[i].Address = addresses[i]
+		dbAddrs[i].Expires = expire
+	}
+
+	seen := now.UnixNano()
+	if s.repl != nil {
+		s.repl.send(key, dbAddrs, seen)
+	}
+	return s.db.merge(key, dbAddrs, seen)
+}
+
+func handlePing(w http.ResponseWriter, r *http.Request) {
+	w.WriteHeader(204)
+}
+
+func certificateBytes(req *http.Request) []byte {
+	if req.TLS != nil && len(req.TLS.PeerCertificates) > 0 {
+		return req.TLS.PeerCertificates[0].Raw
+	}
+
+	if hdr := req.Header.Get("X-SSL-Cert"); hdr != "" {
+		bs := []byte(hdr)
+		// The certificate is in PEM format but with spaces for newlines. We
+		// need to reinstate the newlines for the PEM decoder. But we need to
+		// leave the spaces in the BEGIN and END lines - the first and last
+		// space - alone.
+		firstSpace := bytes.Index(bs, []byte(" "))
+		lastSpace := bytes.LastIndex(bs, []byte(" "))
+		for i := firstSpace + 1; i < lastSpace; i++ {
+			if bs[i] == ' ' {
+				bs[i] = '\n'
+			}
+		}
+		block, _ := pem.Decode(bs)
+		if block == nil {
+			// Decoding failed
+			return nil
+		}
+		return block.Bytes
+	}
+
+	return nil
+}
+
+// fixupAddresses checks the list of addresses, removing invalid ones and
+// replacing unspecified IPs with the given remote IP.
+func fixupAddresses(remote net.IP, addresses []string) []string {
+	fixed := make([]string, 0, len(addresses))
+	for _, annAddr := range addresses {
+		uri, err := url.Parse(annAddr)
+		if err != nil {
+			continue
+		}
+
+		host, port, err := net.SplitHostPort(uri.Host)
+		if err != nil {
+			continue
+		}
+
+		ip := net.ParseIP(host)
+
+		// Some classes of IP are no-go.
+		if ip.IsLoopback() || ip.IsMulticast() {
+			continue
+		}
+
+		if host == "" || ip.IsUnspecified() {
+			// Replace the unspecified IP with the request source.
+
+			// ... unless the request source is the loopback address or
+			// multicast/unspecified (can't happen, really).
+			if remote.IsLoopback() || remote.IsMulticast() || remote.IsUnspecified() {
+				continue
+			}
+
+			// Do not use IPv6 remote address if requested scheme is ...4
+			// (i.e., tcp4, etc.)
+			if strings.HasSuffix(uri.Scheme, "4") && remote.To4() == nil {
+				continue
+			}
+
+			// Do not use IPv4 remote address if requested scheme is ...6
+			if strings.HasSuffix(uri.Scheme, "6") && remote.To4() != nil {
+				continue
+			}
+
+			host = remote.String()
+		}
+
+		uri.Host = net.JoinHostPort(host, port)
+		fixed = append(fixed, uri.String())
+	}
+
+	return fixed
+}
+
+type loggingResponseWriter struct {
+	http.ResponseWriter
+	statusCode int
+}
+
+func NewLoggingResponseWriter(w http.ResponseWriter) *loggingResponseWriter {
+	return &loggingResponseWriter{w, http.StatusOK}
+}
+
+func (lrw *loggingResponseWriter) WriteHeader(code int) {
+	lrw.statusCode = code
+	lrw.ResponseWriter.WriteHeader(code)
+}
+
+func addressStrs(dbAddrs []DatabaseAddress) []string {
+	res := make([]string, len(dbAddrs))
+	for i, a := range dbAddrs {
+		res[i] = a.Address
+	}
+	return res
+}
+
+func errorRetryAfterString() string {
+	return strconv.Itoa(errorRetryAfterSeconds + rand.Intn(errorRetryFuzzSeconds))
+}
+
+func notFoundRetryAfterString(misses int) string {
+	retryAfterS := notFoundRetryMinSeconds + notFoundRetryIncSeconds*misses
+	if retryAfterS > notFoundRetryMaxSeconds {
+		retryAfterS = notFoundRetryMaxSeconds
+	}
+	retryAfterS += rand.Intn(notFoundRetryFuzzSeconds)
+	return strconv.Itoa(retryAfterS)
+}
+
+func reannounceAfterString() string {
+	return strconv.Itoa(reannounceAfterSeconds + rand.Intn(reannounzeFuzzSeconds))
+}
--- a/cmd/stdiscosrv/apisrv_test.go
+++ b/cmd/stdiscosrv/apisrv_test.go
@@ -0,0 +1,65 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"fmt"
+	"net"
+	"testing"
+)
+
+func TestFixupAddresses(t *testing.T) {
+	cases := []struct {
+		remote net.IP
+		in     []string
+		out    []string
+	}{
+		{ // verbatim passthrough
+			in:  []string{"tcp://1.2.3.4:22000"},
+			out: []string{"tcp://1.2.3.4:22000"},
+		}, { // unspecified replaced by remote
+			remote: net.ParseIP("1.2.3.4"),
+			in:     []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
+			out:    []string{"tcp://1.2.3.4:22000", "tcp://192.0.2.42:22000"},
+		}, { // unspecified not used as replacement
+			remote: net.ParseIP("0.0.0.0"),
+			in:     []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
+			out:    []string{"tcp://192.0.2.42:22000"},
+		}, { // unspecified not used as replacement
+			remote: net.ParseIP("::"),
+			in:     []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
+			out:    []string{"tcp://192.0.2.42:22000"},
+		}, { // localhost not used as replacement
+			remote: net.ParseIP("127.0.0.1"),
+			in:     []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
+			out:    []string{"tcp://192.0.2.42:22000"},
+		}, { // localhost not used as replacement
+			remote: net.ParseIP("::1"),
+			in:     []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
+			out:    []string{"tcp://192.0.2.42:22000"},
+		}, { // multicast not used as replacement
+			remote: net.ParseIP("224.0.0.1"),
+			in:     []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
+			out:    []string{"tcp://192.0.2.42:22000"},
+		}, { // multicast not used as replacement
+			remote: net.ParseIP("ff80::42"),
+			in:     []string{"tcp://:22000", "tcp://192.0.2.42:22000"},
+			out:    []string{"tcp://192.0.2.42:22000"},
+		}, { // explicitly announced weirdness is also filtered
+			remote: net.ParseIP("192.0.2.42"),
+			in:     []string{"tcp://:22000", "tcp://127.1.2.3:22000", "tcp://[::1]:22000", "tcp://[ff80::42]:22000"},
+			out:    []string{"tcp://192.0.2.42:22000"},
+		},
+	}
+
+	for _, tc := range cases {
+		out := fixupAddresses(tc.remote, tc.in)
+		if fmt.Sprint(out) != fmt.Sprint(tc.out) {
+			t.Errorf("fixupAddresses(%v, %v) => %v, expected %v", tc.remote, tc.in, out, tc.out)
+		}
+	}
+}
--- a/cmd/stdiscosrv/clean.go
+++ b/cmd/stdiscosrv/clean.go
@@ -1,75 +0,0 @@
-// Copyright (C) 2014-2015 Jakob Borg and Contributors (see the CONTRIBUTORS file).
-
-package main
-
-import (
-	"database/sql"
-	"log"
-	"time"
-)
-
-type cleansrv struct {
-	intv time.Duration
-	db   *sql.DB
-	prep map[string]*sql.Stmt
-}
-
-func (s *cleansrv) Serve() {
-	for {
-		time.Sleep(next(s.intv))
-
-		err := s.cleanOldEntries()
-		if err != nil {
-			log.Println("Clean:", err)
-		}
-	}
-}
-
-func (s *cleansrv) Stop() {
-	panic("stop unimplemented")
-}
-
-func (s *cleansrv) cleanOldEntries() (err error) {
-	var tx *sql.Tx
-	tx, err = s.db.Begin()
-	if err != nil {
-		return err
-	}
-
-	defer func() {
-		if err == nil {
-			err = tx.Commit()
-		} else {
-			tx.Rollback()
-		}
-	}()
-
-	res, err := tx.Stmt(s.prep["cleanAddress"]).Exec()
-	if err != nil {
-		return err
-	}
-	if rows, _ := res.RowsAffected(); rows > 0 {
-		log.Printf("Clean: %d old addresses", rows)
-	}
-
-	res, err = tx.Stmt(s.prep["cleanDevice"]).Exec()
-	if err != nil {
-		return err
-	}
-	if rows, _ := res.RowsAffected(); rows > 0 {
-		log.Printf("Clean: %d old devices", rows)
-	}
-
-	var devs, addrs int
-	row := tx.Stmt(s.prep["countDevice"]).QueryRow()
-	if err = row.Scan(&devs); err != nil {
-		return err
-	}
-	row = tx.Stmt(s.prep["countAddress"]).QueryRow()
-	if err = row.Scan(&addrs); err != nil {
-		return err
-	}
-
-	log.Printf("Database: %d devices, %d addresses", devs, addrs)
-	return nil
-}
--- a/cmd/stdiscosrv/database.go
+++ b/cmd/stdiscosrv/database.go
@@ -0,0 +1,354 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+//go:generate go run ../../script/protofmt.go database.proto
+//go:generate protoc -I ../../ -I . --gogofast_out=. database.proto
+
+package main
+
+import (
+	"sort"
+	"time"
+
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+type clock interface {
+	Now() time.Time
+}
+
+type defaultClock struct{}
+
+func (defaultClock) Now() time.Time {
+	return time.Now()
+}
+
+type database interface {
+	put(key string, rec DatabaseRecord) error
+	merge(key string, addrs []DatabaseAddress, seen int64) error
+	get(key string) (DatabaseRecord, error)
+}
+
+type levelDBStore struct {
+	db         *leveldb.DB
+	inbox      chan func()
+	stop       chan struct{}
+	clock      clock
+	marshalBuf []byte
+}
+
+func newLevelDBStore(dir string) (*levelDBStore, error) {
+	db, err := leveldb.OpenFile(dir, levelDBOptions)
+	if err != nil {
+		return nil, err
+	}
+	return &levelDBStore{
+		db:    db,
+		inbox: make(chan func(), 16),
+		stop:  make(chan struct{}),
+		clock: defaultClock{},
+	}, nil
+}
+
+func (s *levelDBStore) put(key string, rec DatabaseRecord) error {
+	t0 := time.Now()
+	defer func() {
+		databaseOperationSeconds.WithLabelValues(dbOpPut).Observe(time.Since(t0).Seconds())
+	}()
+
+	rc := make(chan error)
+
+	s.inbox <- func() {
+		size := rec.Size()
+		if len(s.marshalBuf) < size {
+			s.marshalBuf = make([]byte, size)
+		}
+		n, _ := rec.MarshalTo(s.marshalBuf)
+		rc <- s.db.Put([]byte(key), s.marshalBuf[:n], nil)
+	}
+
+	err := <-rc
+	if err != nil {
+		databaseOperations.WithLabelValues(dbOpPut, dbResError).Inc()
+	} else {
+		databaseOperations.WithLabelValues(dbOpPut, dbResSuccess).Inc()
+	}
+
+	return err
+}
+
+func (s *levelDBStore) merge(key string, addrs []DatabaseAddress, seen int64) error {
+	t0 := time.Now()
+	defer func() {
+		databaseOperationSeconds.WithLabelValues(dbOpMerge).Observe(time.Since(t0).Seconds())
+	}()
+
+	rc := make(chan error)
+	newRec := DatabaseRecord{
+		Addresses: addrs,
+		Seen:      seen,
+	}
+
+	s.inbox <- func() {
+		// grab the existing record
+		oldRec, err := s.get(key)
+		if err != nil {
+			// "not found" is not an error from get, so this is serious
+			// stuff only
+			rc <- err
+			return
+		}
+		newRec = merge(newRec, oldRec)
+
+		// We replicate s.put() functionality here ourselves instead of
+		// calling it because we want to serialize our get above together
+		// with the put in the same function.
+		size := newRec.Size()
+		if len(s.marshalBuf) < size {
+			s.marshalBuf = make([]byte, size)
+		}
+		n, _ := newRec.MarshalTo(s.marshalBuf)
+		rc <- s.db.Put([]byte(key), s.marshalBuf[:n], nil)
+	}
+
+	err := <-rc
+	if err != nil {
+		databaseOperations.WithLabelValues(dbOpMerge, dbResError).Inc()
+	} else {
+		databaseOperations.WithLabelValues(dbOpMerge, dbResSuccess).Inc()
+	}
+
+	return err
+}
+
+func (s *levelDBStore) get(key string) (DatabaseRecord, error) {
+	t0 := time.Now()
+	defer func() {
+		databaseOperationSeconds.WithLabelValues(dbOpGet).Observe(time.Since(t0).Seconds())
+	}()
+
+	keyBs := []byte(key)
+	val, err := s.db.Get(keyBs, nil)
+	if err == leveldb.ErrNotFound {
+		databaseOperations.WithLabelValues(dbOpGet, dbResNotFound).Inc()
+		return DatabaseRecord{}, nil
+	}
+	if err != nil {
+		databaseOperations.WithLabelValues(dbOpGet, dbResError).Inc()
+		return DatabaseRecord{}, err
+	}
+
+	var rec DatabaseRecord
+
+	if err := rec.Unmarshal(val); err != nil {
+		databaseOperations.WithLabelValues(dbOpGet, dbResUnmarshalError).Inc()
+		return DatabaseRecord{}, nil
+	}
+
+	rec.Addresses = expire(rec.Addresses, s.clock.Now().UnixNano())
+	databaseOperations.WithLabelValues(dbOpGet, dbResSuccess).Inc()
+	return rec, nil
+}
+
+func (s *levelDBStore) Serve() {
+	t := time.NewTimer(0)
+	defer t.Stop()
+	defer s.db.Close()
+
+	// Start the statistics serve routine. It will exit with us when
+	// statisticsTrigger is closed.
+	statisticsTrigger := make(chan struct{})
+	statisticsDone := make(chan struct{})
+	go s.statisticsServe(statisticsTrigger, statisticsDone)
+
+loop:
+	for {
+		select {
+		case fn := <-s.inbox:
+			// Run function in serialized order.
+			fn()
+
+		case <-t.C:
+			// Trigger the statistics routine to do its thing in the
+			// background.
+			statisticsTrigger <- struct{}{}
+
+		case <-statisticsDone:
+			// The statistics routine is done with one iteratation, schedule
+			// the next.
+			t.Reset(databaseStatisticsInterval)
+
+		case <-s.stop:
+			// We're done.
+			close(statisticsTrigger)
+			break loop
+		}
+	}
+
+	// Also wait for statisticsServe to return
+	<-statisticsDone
+}
+
+func (s *levelDBStore) statisticsServe(trigger <-chan struct{}, done chan<- struct{}) {
+	defer close(done)
+
+	for range trigger {
+		t0 := time.Now()
+		nowNanos := t0.UnixNano()
+		cutoff24h := t0.Add(-24 * time.Hour).UnixNano()
+		cutoff1w := t0.Add(-7 * 24 * time.Hour).UnixNano()
+		cutoff2Mon := t0.Add(-60 * 24 * time.Hour).UnixNano()
+		current, last24h, last1w, inactive, errors := 0, 0, 0, 0, 0
+
+		iter := s.db.NewIterator(&util.Range{}, nil)
+		for iter.Next() {
+			// Attempt to unmarshal the record and count the
+			// failure if there's something wrong with it.
+			var rec DatabaseRecord
+			if err := rec.Unmarshal(iter.Value()); err != nil {
+				errors++
+				continue
+			}
+
+			// If there are addresses that have not expired it's a current
+			// record, otherwise account it based on when it was last seen
+			// (last 24 hours or last week) or finally as inactice.
+			switch {
+			case len(expire(rec.Addresses, nowNanos)) > 0:
+				current++
+			case rec.Seen > cutoff24h:
+				last24h++
+			case rec.Seen > cutoff1w:
+				last1w++
+			case rec.Seen > cutoff2Mon:
+				inactive++
+			case rec.Missed < cutoff2Mon:
+				// It hasn't been seen lately and we haven't recorded
+				// someone asking for this device in a long time either;
+				// delete the record.
+				if err := s.db.Delete(iter.Key(), nil); err != nil {
+					databaseOperations.WithLabelValues(dbOpDelete, dbResError).Inc()
+				} else {
+					databaseOperations.WithLabelValues(dbOpDelete, dbResSuccess).Inc()
+				}
+			default:
+				inactive++
+			}
+		}
+
+		iter.Release()
+
+		databaseKeys.WithLabelValues("current").Set(float64(current))
+		databaseKeys.WithLabelValues("last24h").Set(float64(last24h))
+		databaseKeys.WithLabelValues("last1w").Set(float64(last1w))
+		databaseKeys.WithLabelValues("inactive").Set(float64(inactive))
+		databaseKeys.WithLabelValues("error").Set(float64(errors))
+		databaseStatisticsSeconds.Set(time.Since(t0).Seconds())
+
+		// Signal that we are done and can be scheduled again.
+		done <- struct{}{}
+	}
+}
+
+func (s *levelDBStore) Stop() {
+	close(s.stop)
+}
+
+// merge returns the merged result of the two database records a and b. The
+// result is the union of the two address sets, with the newer expiry time
+// chosen for any duplicates.
+func merge(a, b DatabaseRecord) DatabaseRecord {
+	// Both lists must be sorted for this to work.
+	sort.Slice(a.Addresses, func(i, j int) bool {
+		return a.Addresses[i].Address < a.Addresses[j].Address
+	})
+	sort.Slice(b.Addresses, func(i, j int) bool {
+		return b.Addresses[i].Address < b.Addresses[j].Address
+	})
+
+	res := DatabaseRecord{
+		Addresses: make([]DatabaseAddress, 0, len(a.Addresses)+len(b.Addresses)),
+		Seen:      a.Seen,
+	}
+	if b.Seen > a.Seen {
+		res.Seen = b.Seen
+	}
+
+	aIdx := 0
+	bIdx := 0
+	aAddrs := a.Addresses
+	bAddrs := b.Addresses
+loop:
+	for {
+		switch {
+		case aIdx == len(aAddrs) && bIdx == len(bAddrs):
+			// both lists are exhausted, we are done
+			break loop
+
+		case aIdx == len(aAddrs):
+			// a is exhausted, pick from b and continue
+			res.Addresses = append(res.Addresses, bAddrs[bIdx])
+			bIdx++
+			continue
+
+		case bIdx == len(bAddrs):
+			// b is exhausted, pick from a and continue
+			res.Addresses = append(res.Addresses, aAddrs[aIdx])
+			aIdx++
+			continue
+		}
+
+		// We have values left on both sides.
+		aVal := aAddrs[aIdx]
+		bVal := bAddrs[bIdx]
+
+		switch {
+		case aVal.Address == bVal.Address:
+			// update for same address, pick newer
+			if aVal.Expires > bVal.Expires {
+				res.Addresses = append(res.Addresses, aVal)
+			} else {
+				res.Addresses = append(res.Addresses, bVal)
+			}
+			aIdx++
+			bIdx++
+
+		case aVal.Address < bVal.Address:
+			// a is smallest, pick it and continue
+			res.Addresses = append(res.Addresses, aVal)
+			aIdx++
+
+		default:
+			// b is smallest, pick it and continue
+			res.Addresses = append(res.Addresses, bVal)
+			bIdx++
+		}
+	}
+	return res
+}
+
+// expire returns the list of addresses after removing expired entries.
+// Expiration happen in place, so the slice given as the parameter is
+// destroyed. Internal order is not preserved.
+func expire(addrs []DatabaseAddress, now int64) []DatabaseAddress {
+	i := 0
+	for i < len(addrs) {
+		if addrs[i].Expires < now {
+			// This item is expired. Replace it with the last in the list
+			// (noop if we are at the last item).
+			addrs[i] = addrs[len(addrs)-1]
+			// Wipe the last item of the list to release references to
+			// strings and stuff.
+			addrs[len(addrs)-1] = DatabaseAddress{}
+			// Shorten the slice.
+			addrs = addrs[:len(addrs)-1]
+			continue
+		}
+		i++
+	}
+	return addrs
+}
--- a/cmd/stdiscosrv/database.pb.go
+++ b/cmd/stdiscosrv/database.pb.go
@@ -0,0 +1,836 @@
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: database.proto
+
+package main
+
+import proto "github.com/gogo/protobuf/proto"
+import fmt "fmt"
+import math "math"
+import _ "github.com/gogo/protobuf/gogoproto"
+
+import io "io"
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.GoGoProtoPackageIsVersion2 // please upgrade the proto package
+
+type DatabaseRecord struct {
+	Addresses []DatabaseAddress `protobuf:"bytes,1,rep,name=addresses,proto3" json:"addresses"`
+	Misses    int32             `protobuf:"varint,2,opt,name=misses,proto3" json:"misses,omitempty"`
+	Seen      int64             `protobuf:"varint,3,opt,name=seen,proto3" json:"seen,omitempty"`
+	Missed    int64             `protobuf:"varint,4,opt,name=missed,proto3" json:"missed,omitempty"`
+}
+
+func (m *DatabaseRecord) Reset()         { *m = DatabaseRecord{} }
+func (m *DatabaseRecord) String() string { return proto.CompactTextString(m) }
+func (*DatabaseRecord) ProtoMessage()    {}
+func (*DatabaseRecord) Descriptor() ([]byte, []int) {
+	return fileDescriptor_database_0f49e029703a04f5, []int{0}
+}
+func (m *DatabaseRecord) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *DatabaseRecord) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_DatabaseRecord.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalTo(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (dst *DatabaseRecord) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_DatabaseRecord.Merge(dst, src)
+}
+func (m *DatabaseRecord) XXX_Size() int {
+	return m.Size()
+}
+func (m *DatabaseRecord) XXX_DiscardUnknown() {
+	xxx_messageInfo_DatabaseRecord.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_DatabaseRecord proto.InternalMessageInfo
+
+type ReplicationRecord struct {
+	Key       string            `protobuf:"bytes,1,opt,name=key,proto3" json:"key,omitempty"`
+	Addresses []DatabaseAddress `protobuf:"bytes,2,rep,name=addresses,proto3" json:"addresses"`
+	Seen      int64             `protobuf:"varint,3,opt,name=seen,proto3" json:"seen,omitempty"`
+}
+
+func (m *ReplicationRecord) Reset()         { *m = ReplicationRecord{} }
+func (m *ReplicationRecord) String() string { return proto.CompactTextString(m) }
+func (*ReplicationRecord) ProtoMessage()    {}
+func (*ReplicationRecord) Descriptor() ([]byte, []int) {
+	return fileDescriptor_database_0f49e029703a04f5, []int{1}
+}
+func (m *ReplicationRecord) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *ReplicationRecord) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_ReplicationRecord.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalTo(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (dst *ReplicationRecord) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_ReplicationRecord.Merge(dst, src)
+}
+func (m *ReplicationRecord) XXX_Size() int {
+	return m.Size()
+}
+func (m *ReplicationRecord) XXX_DiscardUnknown() {
+	xxx_messageInfo_ReplicationRecord.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_ReplicationRecord proto.InternalMessageInfo
+
+type DatabaseAddress struct {
+	Address string `protobuf:"bytes,1,opt,name=address,proto3" json:"address,omitempty"`
+	Expires int64  `protobuf:"varint,2,opt,name=expires,proto3" json:"expires,omitempty"`
+}
+
+func (m *DatabaseAddress) Reset()         { *m = DatabaseAddress{} }
+func (m *DatabaseAddress) String() string { return proto.CompactTextString(m) }
+func (*DatabaseAddress) ProtoMessage()    {}
+func (*DatabaseAddress) Descriptor() ([]byte, []int) {
+	return fileDescriptor_database_0f49e029703a04f5, []int{2}
+}
+func (m *DatabaseAddress) XXX_Unmarshal(b []byte) error {
+	return m.Unmarshal(b)
+}
+func (m *DatabaseAddress) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	if deterministic {
+		return xxx_messageInfo_DatabaseAddress.Marshal(b, m, deterministic)
+	} else {
+		b = b[:cap(b)]
+		n, err := m.MarshalTo(b)
+		if err != nil {
+			return nil, err
+		}
+		return b[:n], nil
+	}
+}
+func (dst *DatabaseAddress) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_DatabaseAddress.Merge(dst, src)
+}
+func (m *DatabaseAddress) XXX_Size() int {
+	return m.Size()
+}
+func (m *DatabaseAddress) XXX_DiscardUnknown() {
+	xxx_messageInfo_DatabaseAddress.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_DatabaseAddress proto.InternalMessageInfo
+
+func init() {
+	proto.RegisterType((*DatabaseRecord)(nil), "main.DatabaseRecord")
+	proto.RegisterType((*ReplicationRecord)(nil), "main.ReplicationRecord")
+	proto.RegisterType((*DatabaseAddress)(nil), "main.DatabaseAddress")
+}
+func (m *DatabaseRecord) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *DatabaseRecord) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if len(m.Addresses) > 0 {
+		for _, msg := range m.Addresses {
+			dAtA[i] = 0xa
+			i++
+			i = encodeVarintDatabase(dAtA, i, uint64(msg.Size()))
+			n, err := msg.MarshalTo(dAtA[i:])
+			if err != nil {
+				return 0, err
+			}
+			i += n
+		}
+	}
+	if m.Misses != 0 {
+		dAtA[i] = 0x10
+		i++
+		i = encodeVarintDatabase(dAtA, i, uint64(m.Misses))
+	}
+	if m.Seen != 0 {
+		dAtA[i] = 0x18
+		i++
+		i = encodeVarintDatabase(dAtA, i, uint64(m.Seen))
+	}
+	if m.Missed != 0 {
+		dAtA[i] = 0x20
+		i++
+		i = encodeVarintDatabase(dAtA, i, uint64(m.Missed))
+	}
+	return i, nil
+}
+
+func (m *ReplicationRecord) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *ReplicationRecord) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if len(m.Key) > 0 {
+		dAtA[i] = 0xa
+		i++
+		i = encodeVarintDatabase(dAtA, i, uint64(len(m.Key)))
+		i += copy(dAtA[i:], m.Key)
+	}
+	if len(m.Addresses) > 0 {
+		for _, msg := range m.Addresses {
+			dAtA[i] = 0x12
+			i++
+			i = encodeVarintDatabase(dAtA, i, uint64(msg.Size()))
+			n, err := msg.MarshalTo(dAtA[i:])
+			if err != nil {
+				return 0, err
+			}
+			i += n
+		}
+	}
+	if m.Seen != 0 {
+		dAtA[i] = 0x18
+		i++
+		i = encodeVarintDatabase(dAtA, i, uint64(m.Seen))
+	}
+	return i, nil
+}
+
+func (m *DatabaseAddress) Marshal() (dAtA []byte, err error) {
+	size := m.Size()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalTo(dAtA)
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *DatabaseAddress) MarshalTo(dAtA []byte) (int, error) {
+	var i int
+	_ = i
+	var l int
+	_ = l
+	if len(m.Address) > 0 {
+		dAtA[i] = 0xa
+		i++
+		i = encodeVarintDatabase(dAtA, i, uint64(len(m.Address)))
+		i += copy(dAtA[i:], m.Address)
+	}
+	if m.Expires != 0 {
+		dAtA[i] = 0x10
+		i++
+		i = encodeVarintDatabase(dAtA, i, uint64(m.Expires))
+	}
+	return i, nil
+}
+
+func encodeVarintDatabase(dAtA []byte, offset int, v uint64) int {
+	for v >= 1<<7 {
+		dAtA[offset] = uint8(v&0x7f | 0x80)
+		v >>= 7
+		offset++
+	}
+	dAtA[offset] = uint8(v)
+	return offset + 1
+}
+func (m *DatabaseRecord) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if len(m.Addresses) > 0 {
+		for _, e := range m.Addresses {
+			l = e.Size()
+			n += 1 + l + sovDatabase(uint64(l))
+		}
+	}
+	if m.Misses != 0 {
+		n += 1 + sovDatabase(uint64(m.Misses))
+	}
+	if m.Seen != 0 {
+		n += 1 + sovDatabase(uint64(m.Seen))
+	}
+	if m.Missed != 0 {
+		n += 1 + sovDatabase(uint64(m.Missed))
+	}
+	return n
+}
+
+func (m *ReplicationRecord) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	l = len(m.Key)
+	if l > 0 {
+		n += 1 + l + sovDatabase(uint64(l))
+	}
+	if len(m.Addresses) > 0 {
+		for _, e := range m.Addresses {
+			l = e.Size()
+			n += 1 + l + sovDatabase(uint64(l))
+		}
+	}
+	if m.Seen != 0 {
+		n += 1 + sovDatabase(uint64(m.Seen))
+	}
+	return n
+}
+
+func (m *DatabaseAddress) Size() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	l = len(m.Address)
+	if l > 0 {
+		n += 1 + l + sovDatabase(uint64(l))
+	}
+	if m.Expires != 0 {
+		n += 1 + sovDatabase(uint64(m.Expires))
+	}
+	return n
+}
+
+func sovDatabase(x uint64) (n int) {
+	for {
+		n++
+		x >>= 7
+		if x == 0 {
+			break
+		}
+	}
+	return n
+}
+func sozDatabase(x uint64) (n int) {
+	return sovDatabase(uint64((x << 1) ^ uint64((int64(x) >> 63))))
+}
+func (m *DatabaseRecord) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowDatabase
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: DatabaseRecord: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: DatabaseRecord: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Addresses", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthDatabase
+			}
+			postIndex := iNdEx + msglen
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Addresses = append(m.Addresses, DatabaseAddress{})
+			if err := m.Addresses[len(m.Addresses)-1].Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Misses", wireType)
+			}
+			m.Misses = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Misses |= (int32(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 3:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Seen", wireType)
+			}
+			m.Seen = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Seen |= (int64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 4:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Missed", wireType)
+			}
+			m.Missed = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Missed |= (int64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		default:
+			iNdEx = preIndex
+			skippy, err := skipDatabase(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthDatabase
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *ReplicationRecord) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowDatabase
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: ReplicationRecord: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: ReplicationRecord: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Key", wireType)
+			}
+			var stringLen uint64
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				stringLen |= (uint64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			intStringLen := int(stringLen)
+			if intStringLen < 0 {
+				return ErrInvalidLengthDatabase
+			}
+			postIndex := iNdEx + intStringLen
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Key = string(dAtA[iNdEx:postIndex])
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Addresses", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return ErrInvalidLengthDatabase
+			}
+			postIndex := iNdEx + msglen
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Addresses = append(m.Addresses, DatabaseAddress{})
+			if err := m.Addresses[len(m.Addresses)-1].Unmarshal(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		case 3:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Seen", wireType)
+			}
+			m.Seen = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Seen |= (int64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		default:
+			iNdEx = preIndex
+			skippy, err := skipDatabase(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthDatabase
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *DatabaseAddress) Unmarshal(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return ErrIntOverflowDatabase
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: DatabaseAddress: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: DatabaseAddress: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Address", wireType)
+			}
+			var stringLen uint64
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				stringLen |= (uint64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			intStringLen := int(stringLen)
+			if intStringLen < 0 {
+				return ErrInvalidLengthDatabase
+			}
+			postIndex := iNdEx + intStringLen
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Address = string(dAtA[iNdEx:postIndex])
+			iNdEx = postIndex
+		case 2:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Expires", wireType)
+			}
+			m.Expires = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.Expires |= (int64(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		default:
+			iNdEx = preIndex
+			skippy, err := skipDatabase(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if skippy < 0 {
+				return ErrInvalidLengthDatabase
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func skipDatabase(dAtA []byte) (n int, err error) {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return 0, ErrIntOverflowDatabase
+			}
+			if iNdEx >= l {
+				return 0, io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= (uint64(b) & 0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		wireType := int(wire & 0x7)
+		switch wireType {
+		case 0:
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				iNdEx++
+				if dAtA[iNdEx-1] < 0x80 {
+					break
+				}
+			}
+			return iNdEx, nil
+		case 1:
+			iNdEx += 8
+			return iNdEx, nil
+		case 2:
+			var length int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return 0, ErrIntOverflowDatabase
+				}
+				if iNdEx >= l {
+					return 0, io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				length |= (int(b) & 0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			iNdEx += length
+			if length < 0 {
+				return 0, ErrInvalidLengthDatabase
+			}
+			return iNdEx, nil
+		case 3:
+			for {
+				var innerWire uint64
+				var start int = iNdEx
+				for shift := uint(0); ; shift += 7 {
+					if shift >= 64 {
+						return 0, ErrIntOverflowDatabase
+					}
+					if iNdEx >= l {
+						return 0, io.ErrUnexpectedEOF
+					}
+					b := dAtA[iNdEx]
+					iNdEx++
+					innerWire |= (uint64(b) & 0x7F) << shift
+					if b < 0x80 {
+						break
+					}
+				}
+				innerWireType := int(innerWire & 0x7)
+				if innerWireType == 4 {
+					break
+				}
+				next, err := skipDatabase(dAtA[start:])
+				if err != nil {
+					return 0, err
+				}
+				iNdEx = start + next
+			}
+			return iNdEx, nil
+		case 4:
+			return iNdEx, nil
+		case 5:
+			iNdEx += 4
+			return iNdEx, nil
+		default:
+			return 0, fmt.Errorf("proto: illegal wireType %d", wireType)
+		}
+	}
+	panic("unreachable")
+}
+
+var (
+	ErrInvalidLengthDatabase = fmt.Errorf("proto: negative length found during unmarshaling")
+	ErrIntOverflowDatabase   = fmt.Errorf("proto: integer overflow")
+)
+
+func init() { proto.RegisterFile("database.proto", fileDescriptor_database_0f49e029703a04f5) }
+
+var fileDescriptor_database_0f49e029703a04f5 = []byte{
+	// 270 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0x94, 0x90, 0x41, 0x4a, 0xc4, 0x30,
+	0x18, 0x85, 0x9b, 0x49, 0x1d, 0x99, 0x08, 0xa3, 0x06, 0x94, 0x20, 0x12, 0x4b, 0xdd, 0x74, 0xd5,
+	0x01, 0x5d, 0xb9, 0x74, 0xd0, 0x0b, 0xe4, 0x06, 0xe9, 0xe4, 0x77, 0x08, 0x3a, 0x4d, 0x49, 0x2a,
+	0xe8, 0x29, 0xf4, 0x58, 0x5d, 0xce, 0xd2, 0x95, 0x68, 0x7b, 0x11, 0x69, 0x26, 0x55, 0x14, 0x37,
+	0xb3, 0x7b, 0xdf, 0xff, 0xbf, 0x97, 0xbc, 0x84, 0x4c, 0x95, 0xac, 0x65, 0x21, 0x1d, 0xe4, 0x95,
+	0x35, 0xb5, 0xa1, 0xf1, 0x4a, 0xea, 0xf2, 0xe4, 0xdc, 0x42, 0x65, 0xdc, 0xcc, 0x8f, 0x8a, 0xc7,
+	0xbb, 0xd9, 0xd2, 0x2c, 0x8d, 0x07, 0xaf, 0x36, 0xd6, 0xf4, 0x05, 0x91, 0xe9, 0x4d, 0x48, 0x0b,
+	0x58, 0x18, 0xab, 0xe8, 0x15, 0x99, 0x48, 0xa5, 0x2c, 0x38, 0x07, 0x8e, 0xa1, 0x04, 0x67, 0x7b,
+	0x17, 0x47, 0x79, 0x7f, 0x62, 0x3e, 0x18, 0xaf, 0x37, 0xeb, 0x79, 0xdc, 0xbc, 0x9f, 0x45, 0xe2,
+	0xc7, 0x4d, 0x8f, 0xc9, 0x78, 0xa5, 0x7d, 0x6e, 0x94, 0xa0, 0x6c, 0x47, 0x04, 0xa2, 0x94, 0xc4,
+	0x0e, 0xa0, 0x64, 0x38, 0x41, 0x19, 0x16, 0x5e, 0x7f, 0x7b, 0x15, 0x8b, 0xfd, 0x34, 0x50, 0x5a,
+	0x93, 0x43, 0x01, 0xd5, 0x83, 0x5e, 0xc8, 0x5a, 0x9b, 0x32, 0x74, 0x3a, 0x20, 0xf8, 0x1e, 0x9e,
+	0x19, 0x4a, 0x50, 0x36, 0x11, 0xbd, 0xfc, 0xdd, 0x72, 0xb4, 0x55, 0xcb, 0x7f, 0xda, 0xa4, 0xb7,
+	0x64, 0xff, 0x4f, 0x8e, 0x32, 0xb2, 0x1b, 0x32, 0xe1, 0xde, 0x01, 0xfb, 0x0d, 0x3c, 0x55, 0xda,
+	0x86, 0x77, 0x62, 0x31, 0xe0, 0xfc, 0xb4, 0xf9, 0xe4, 0x51, 0xd3, 0x72, 0xb4, 0x6e, 0x39, 0xfa,
+	0x68, 0x39, 0x7a, 0xed, 0x78, 0xb4, 0xee, 0x78, 0xf4, 0xd6, 0xf1, 0xa8, 0x18, 0xfb, 0x3f, 0xbf,
+	0xfc, 0x0a, 0x00, 0x00, 0xff, 0xff, 0x7a, 0xa2, 0xf6, 0x1e, 0xb0, 0x01, 0x00, 0x00,
+}
--- a/cmd/stdiscosrv/database.proto
+++ b/cmd/stdiscosrv/database.proto
@@ -0,0 +1,36 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+syntax = "proto3";
+
+package main;
+
+import "repos/protobuf/gogoproto/gogo.proto";
+
+option (gogoproto.goproto_getters_all) = false;
+option (gogoproto.goproto_unkeyed_all) = false;
+option (gogoproto.goproto_unrecognized_all) = false;
+option (gogoproto.goproto_sizecache_all) = false;
+
+message DatabaseRecord {
+    repeated DatabaseAddress addresses = 1 [(gogoproto.nullable) = false];
+    int32                    misses    = 2; // Number of lookups* without hits
+    int64                    seen      = 3; // Unix nanos, last device announce
+    int64                    missed    = 4; // Unix nanos, last* failed lookup
+}
+
+// *) Not every lookup results in a write, so may not be completely accurate
+
+message ReplicationRecord {
+    string                   key       = 1;
+    repeated DatabaseAddress addresses = 2 [(gogoproto.nullable) = false];
+    int64                    seen      = 3; // Unix nanos, last device announce
+}
+
+message DatabaseAddress {
+    string address = 1;
+    int64  expires = 2; // Unix nanos
+}
--- a/cmd/stdiscosrv/database_test.go
+++ b/cmd/stdiscosrv/database_test.go
@@ -0,0 +1,211 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestDatabaseGetSet(t *testing.T) {
+	os.RemoveAll("_database")
+	defer os.RemoveAll("_database")
+	db, err := newLevelDBStore("_database")
+	if err != nil {
+		t.Fatal(err)
+	}
+	go db.Serve()
+	defer db.Stop()
+
+	// Check missing record
+
+	rec, err := db.get("abcd")
+	if err != nil {
+		t.Error("not found should not be an error")
+	}
+	if len(rec.Addresses) != 0 {
+		t.Error("addresses should be empty")
+	}
+	if rec.Misses != 0 {
+		t.Error("missing should be zero")
+	}
+
+	// Set up a clock
+
+	now := time.Now()
+	tc := &testClock{now}
+	db.clock = tc
+
+	// Put a record
+
+	rec.Addresses = []DatabaseAddress{
+		{Address: "tcp://1.2.3.4:5", Expires: tc.Now().Add(time.Minute).UnixNano()},
+	}
+	if err := db.put("abcd", rec); err != nil {
+		t.Fatal(err)
+	}
+
+	// Verify it
+
+	rec, err = db.get("abcd")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(rec.Addresses) != 1 {
+		t.Log(rec.Addresses)
+		t.Fatal("should have one address")
+	}
+	if rec.Addresses[0].Address != "tcp://1.2.3.4:5" {
+		t.Log(rec.Addresses)
+		t.Error("incorrect address")
+	}
+
+	// Wind the clock one half expiry, and merge in a new address
+
+	tc.wind(30 * time.Second)
+
+	addrs := []DatabaseAddress{
+		{Address: "tcp://6.7.8.9:0", Expires: tc.Now().Add(time.Minute).UnixNano()},
+	}
+	if err := db.merge("abcd", addrs, tc.Now().UnixNano()); err != nil {
+		t.Fatal(err)
+	}
+
+	// Verify it
+
+	rec, err = db.get("abcd")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(rec.Addresses) != 2 {
+		t.Log(rec.Addresses)
+		t.Fatal("should have two addresses")
+	}
+	if rec.Addresses[0].Address != "tcp://1.2.3.4:5" {
+		t.Log(rec.Addresses)
+		t.Error("incorrect address[0]")
+	}
+	if rec.Addresses[1].Address != "tcp://6.7.8.9:0" {
+		t.Log(rec.Addresses)
+		t.Error("incorrect address[1]")
+	}
+
+	// Pass the first expiry time
+
+	tc.wind(45 * time.Second)
+
+	// Verify it
+
+	rec, err = db.get("abcd")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(rec.Addresses) != 1 {
+		t.Log(rec.Addresses)
+		t.Fatal("should have one address")
+	}
+	if rec.Addresses[0].Address != "tcp://6.7.8.9:0" {
+		t.Log(rec.Addresses)
+		t.Error("incorrect address")
+	}
+
+	// Put a record with misses
+
+	rec = DatabaseRecord{Misses: 42}
+	if err := db.put("efgh", rec); err != nil {
+		t.Fatal(err)
+	}
+
+	// Verify it
+
+	rec, err = db.get("efgh")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(rec.Addresses) != 0 {
+		t.Log(rec.Addresses)
+		t.Fatal("should have no addresses")
+	}
+	if rec.Misses != 42 {
+		t.Log(rec.Misses)
+		t.Error("incorrect misses")
+	}
+
+	// Set an address
+
+	addrs = []DatabaseAddress{
+		{Address: "tcp://6.7.8.9:0", Expires: tc.Now().Add(time.Minute).UnixNano()},
+	}
+	if err := db.merge("efgh", addrs, tc.Now().UnixNano()); err != nil {
+		t.Fatal(err)
+	}
+
+	// Verify it
+
+	rec, err = db.get("efgh")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(rec.Addresses) != 1 {
+		t.Log(rec.Addresses)
+		t.Fatal("should have one address")
+	}
+	if rec.Misses != 0 {
+		t.Log(rec.Misses)
+		t.Error("should have no misses")
+	}
+}
+
+func TestFilter(t *testing.T) {
+	// all cases are expired with t=10
+	cases := []struct {
+		a []DatabaseAddress
+		b []DatabaseAddress
+	}{
+		{
+			a: nil,
+			b: nil,
+		},
+		{
+			a: []DatabaseAddress{{Address: "a", Expires: 9}, {Address: "b", Expires: 9}, {Address: "c", Expires: 9}},
+			b: []DatabaseAddress{},
+		},
+		{
+			a: []DatabaseAddress{{Address: "a", Expires: 10}},
+			b: []DatabaseAddress{{Address: "a", Expires: 10}},
+		},
+		{
+			a: []DatabaseAddress{{Address: "a", Expires: 10}, {Address: "b", Expires: 10}, {Address: "c", Expires: 10}},
+			b: []DatabaseAddress{{Address: "a", Expires: 10}, {Address: "b", Expires: 10}, {Address: "c", Expires: 10}},
+		},
+		{
+			a: []DatabaseAddress{{Address: "a", Expires: 5}, {Address: "b", Expires: 15}, {Address: "c", Expires: 5}, {Address: "d", Expires: 15}, {Address: "e", Expires: 5}},
+			b: []DatabaseAddress{{Address: "d", Expires: 15}, {Address: "b", Expires: 15}}, // gets reordered
+		},
+	}
+
+	for _, tc := range cases {
+		res := expire(tc.a, 10)
+		if fmt.Sprint(res) != fmt.Sprint(tc.b) {
+			t.Errorf("Incorrect result %v, expected %v", res, tc.b)
+		}
+	}
+}
+
+type testClock struct {
+	now time.Time
+}
+
+func (t *testClock) wind(d time.Duration) {
+	t.now = t.now.Add(d)
+}
+
+func (t *testClock) Now() time.Time {
+	return t.now
+}
--- a/cmd/stdiscosrv/db.go
+++ b/cmd/stdiscosrv/db.go
@@ -1,32 +0,0 @@
-// Copyright (C) 2014-2015 Jakob Borg and Contributors (see the CONTRIBUTORS file).
-
-package main
-
-import (
-	"database/sql"
-	"fmt"
-)
-
-type setupFunc func(db *sql.DB) error
-type compileFunc func(db *sql.DB) (map[string]*sql.Stmt, error)
-
-var (
-	setupFuncs   = make(map[string]setupFunc)
-	compileFuncs = make(map[string]compileFunc)
-)
-
-func register(name string, setup setupFunc, compile compileFunc) {
-	setupFuncs[name] = setup
-	compileFuncs[name] = compile
-}
-
-func setup(backend string, db *sql.DB) (map[string]*sql.Stmt, error) {
-	setup, ok := setupFuncs[backend]
-	if !ok {
-		return nil, fmt.Errorf("Unsupported backend")
-	}
-	if err := setup(db); err != nil {
-		return nil, err
-	}
-	return compileFuncs[backend](db)
-}
--- a/cmd/stdiscosrv/main.go
+++ b/cmd/stdiscosrv/main.go
@@ -1,29 +1,70 @@
-// Copyright (C) 2014-2015 Jakob Borg and Contributors (see the CONTRIBUTORS file).
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.

 package main

 import (
 	"crypto/tls"
-	"database/sql"
 	"flag"
 	"fmt"
 	"log"
+	"net"
+	"net/http"
 	"os"
 	"runtime"
 	"strconv"
+	"strings"
 	"time"

+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/tlsutil"
+	"github.com/syndtr/goleveldb/leveldb/opt"
 	"github.com/thejerf/suture"
 )

 const (
-	minNegCache  = 60        // seconds
-	maxNegCache  = 3600      // seconds
-	maxDeviceAge = 7 * 86400 // one week, in seconds
+	addressExpiryTime          = 2 * time.Hour
+	databaseStatisticsInterval = 5 * time.Minute
+
+	// Reannounce-After is set to reannounceAfterSeconds +
+	// random(reannounzeFuzzSeconds), similar for Retry-After
+	reannounceAfterSeconds = 3300
+	reannounzeFuzzSeconds  = 300
+	errorRetryAfterSeconds = 1500
+	errorRetryFuzzSeconds  = 300
+
+	// Retry for not found is minSeconds + failures * incSeconds +
+	// random(fuzz), where failures is the number of consecutive lookups
+	// with no answer, up to maxSeconds. The fuzz is applied after capping
+	// to maxSeconds.
+	notFoundRetryMinSeconds  = 60
+	notFoundRetryMaxSeconds  = 3540
+	notFoundRetryIncSeconds  = 10
+	notFoundRetryFuzzSeconds = 60
+
+	// How often (in requests) we serialize the missed counter to database.
+	notFoundMissesWriteInterval = 10
+
+	httpReadTimeout    = 5 * time.Second
+	httpWriteTimeout   = 5 * time.Second
+	httpMaxHeaderBytes = 1 << 10
+
+	// Size of the replication outbox channel
+	replicationOutboxSize = 10000
 )

+// These options make the database a little more optimized for writes, at
+// the expense of some memory usage and risk of losing writes in a (system)
+// crash.
+var levelDBOptions = &opt.Options{
+	NoSync:      true,
+	WriteBuffer: 32 << 20, // default 4<<20
+}
+
 var (
 	Version    string
 	BuildStamp string
@@ -43,104 +84,119 @@ func init() {
 }

 var (
-	lruSize     = 10240
-	limitAvg    = 5
-	limitBurst  = 20
-	globalStats stats
-	statsFile   string
-	backend     = "ql"
-	dsn         = getEnvDefault("STDISCOSRV_DB_DSN", "memory://stdiscosrv")
-	certFile    = "cert.pem"
-	keyFile     = "key.pem"
-	debug       = false
-	useHTTP     = false
+	debug = false
 )

 func main() {
-	const (
-		cleanIntv = 1 * time.Hour
-		statsIntv = 5 * time.Minute
-	)
-
 	var listen string
+	var dir string
+	var metricsListen string
+	var replicationListen string
+	var replicationPeers string
+	var certFile string
+	var keyFile string
+	var useHTTP bool

 	log.SetOutput(os.Stdout)
 	log.SetFlags(0)

+	flag.StringVar(&certFile, "cert", "./cert.pem", "Certificate file")
+	flag.StringVar(&dir, "db-dir", "./discovery.db", "Database directory")
+	flag.BoolVar(&debug, "debug", false, "Print debug output")
+	flag.BoolVar(&useHTTP, "http", false, "Listen on HTTP (behind an HTTPS proxy)")
 	flag.StringVar(&listen, "listen", ":8443", "Listen address")
-	flag.IntVar(&lruSize, "limit-cache", lruSize, "Limiter cache entries")
-	flag.IntVar(&limitAvg, "limit-avg", limitAvg, "Allowed average package rate, per 10 s")
-	flag.IntVar(&limitBurst, "limit-burst", limitBurst, "Allowed burst size, packets")
-	flag.StringVar(&statsFile, "stats-file", statsFile, "File to write periodic operation stats to")
-	flag.StringVar(&backend, "db-backend", backend, "Database backend to use")
-	flag.StringVar(&dsn, "db-dsn", dsn, "Database DSN")
-	flag.StringVar(&certFile, "cert", certFile, "Certificate file")
-	flag.StringVar(&keyFile, "key", keyFile, "Key file")
-	flag.BoolVar(&debug, "debug", debug, "Debug")
-	flag.BoolVar(&useHTTP, "http", useHTTP, "Listen on HTTP (behind an HTTPS proxy)")
+	flag.StringVar(&keyFile, "key", "./key.pem", "Key file")
+	flag.StringVar(&metricsListen, "metrics-listen", "", "Metrics listen address")
+	flag.StringVar(&replicationPeers, "replicate", "", "Replication peers, id@address, comma separated")
+	flag.StringVar(&replicationListen, "replication-listen", ":19200", "Replication listen address")
 	flag.Parse()

 	log.Println(LongVersion)

-	var cert tls.Certificate
-	var err error
-	if !useHTTP {
-		cert, err = tls.LoadX509KeyPair(certFile, keyFile)
+	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
+	if err != nil {
+		log.Println("Failed to load keypair. Generating one, this might take a while...")
+		cert, err = tlsutil.NewCertificate(certFile, keyFile, "stdiscosrv")
 		if err != nil {
-			log.Println("Failed to load keypair. Generating one, this might take a while...")
-			cert, err = tlsutil.NewCertificate(certFile, keyFile, "stdiscosrv", 3072)
-			if err != nil {
-				log.Fatalln("Failed to generate X509 key pair:", err)
-			}
+			log.Fatalln("Failed to generate X509 key pair:", err)
 		}
-
-		devID := protocol.NewDeviceID(cert.Certificate[0])
-		log.Println("Server device ID is", devID)
 	}

-	db, err := sql.Open(backend, dsn)
+	devID := protocol.NewDeviceID(cert.Certificate[0])
+	log.Println("Server device ID is", devID)
+
+	// Parse the replication specs, if any.
+	var allowedReplicationPeers []protocol.DeviceID
+	var replicationDestinations []string
+	parts := strings.Split(replicationPeers, ",")
+	for _, part := range parts {
+		fields := strings.Split(part, "@")
+
+		switch len(fields) {
+		case 2:
+			// This is an id@address specification. Grab the address for the
+			// destination list. Try to resolve it once to catch obvious
+			// syntax errors here rather than having the sender service fail
+			// repeatedly later.
+			_, err := net.ResolveTCPAddr("tcp", fields[1])
+			if err != nil {
+				log.Fatalln("Resolving address:", err)
+			}
+			replicationDestinations = append(replicationDestinations, fields[1])
+			fallthrough // N.B.
+
+		case 1:
+			// The first part is always a device ID.
+			id, err := protocol.DeviceIDFromString(fields[0])
+			if err != nil {
+				log.Fatalln("Parsing device ID:", err)
+			}
+			allowedReplicationPeers = append(allowedReplicationPeers, id)
+
+		default:
+			log.Fatalln("Unrecognized replication spec:", part)
+		}
+	}
+
+	// Root of the service tree.
+	main := suture.New("main", suture.Spec{
+		PassThroughPanics: true,
+	})
+
+	// Start the database.
+	db, err := newLevelDBStore(dir)
 	if err != nil {
-		log.Fatalln("sql.Open:", err)
+		log.Fatalln("Open database:", err)
 	}
-	prep, err := setup(backend, db)
-	if err != nil {
-		log.Fatalln("Setup:", err)
+	main.Add(db)
+
+	// Start any replication senders.
+	var repl replicationMultiplexer
+	for _, dst := range replicationDestinations {
+		rs := newReplicationSender(dst, cert, allowedReplicationPeers)
+		main.Add(rs)
+		repl = append(repl, rs)
 	}

-	main := suture.NewSimple("main")
+	// If we have replication configured, start the replication listener.
+	if len(allowedReplicationPeers) > 0 {
+		rl := newReplicationListener(replicationListen, cert, allowedReplicationPeers, db)
+		main.Add(rl)
+	}

-	main.Add(&querysrv{
-		addr: listen,
-		cert: cert,
-		db:   db,
-		prep: prep,
-	})
+	// Start the main API server.
+	qs := newAPISrv(listen, cert, db, repl, useHTTP)
+	main.Add(qs)

-	main.Add(&cleansrv{
-		intv: cleanIntv,
-		db:   db,
-		prep: prep,
-	})
+	// If we have a metrics port configured, start a metrics handler.
+	if metricsListen != "" {
+		go func() {
+			mux := http.NewServeMux()
+			mux.Handle("/metrics", promhttp.Handler())
+			log.Fatal(http.ListenAndServe(metricsListen, mux))
+		}()
+	}

-	main.Add(&statssrv{
-		intv: statsIntv,
-		file: statsFile,
-		db:   db,
-	})
-
-	globalStats.Reset()
+	// Engage!
 	main.Serve()
 }
-
-func getEnvDefault(key, def string) string {
-	if val := os.Getenv(key); val != "" {
-		return val
-	}
-	return def
-}
-
-func next(intv time.Duration) time.Duration {
-	t0 := time.Now()
-	t1 := t0.Add(intv).Truncate(intv)
-	return t1.Sub(t0)
-}
--- a/cmd/stdiscosrv/psql.go
+++ b/cmd/stdiscosrv/psql.go
@@ -1,98 +0,0 @@
-// Copyright (C) 2014-2015 Jakob Borg and Contributors (see the CONTRIBUTORS file).
-
-package main
-
-import (
-	"database/sql"
-	"fmt"
-
-	_ "github.com/lib/pq"
-)
-
-func init() {
-	register("postgres", postgresSetup, postgresCompile)
-}
-
-func postgresSetup(db *sql.DB) error {
-	var err error
-
-	db.SetMaxIdleConns(4)
-	db.SetMaxOpenConns(8)
-
-	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS Devices (
-		DeviceID CHAR(63) NOT NULL PRIMARY KEY,
-		Seen TIMESTAMP NOT NULL
-	)`)
-	if err != nil {
-		return err
-	}
-
-	var tmp string
-	row := db.QueryRow(`SELECT 'DevicesDeviceIDIndex'::regclass`)
-	if err = row.Scan(&tmp); err != nil {
-		_, err = db.Exec(`CREATE INDEX DevicesDeviceIDIndex ON Devices (DeviceID)`)
-	}
-	if err != nil {
-		return err
-	}
-
-	row = db.QueryRow(`SELECT 'DevicesSeenIndex'::regclass`)
-	if err = row.Scan(&tmp); err != nil {
-		_, err = db.Exec(`CREATE INDEX DevicesSeenIndex ON Devices (Seen)`)
-	}
-	if err != nil {
-		return err
-	}
-
-	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS Addresses (
-		DeviceID CHAR(63) NOT NULL,
-		Seen TIMESTAMP NOT NULL,
-		Address VARCHAR(2048) NOT NULL
-	)`)
-	if err != nil {
-		return err
-	}
-
-	row = db.QueryRow(`SELECT 'AddressesDeviceIDSeenIndex'::regclass`)
-	if err = row.Scan(&tmp); err != nil {
-		_, err = db.Exec(`CREATE INDEX AddressesDeviceIDSeenIndex ON Addresses (DeviceID, Seen)`)
-	}
-	if err != nil {
-		return err
-	}
-
-	row = db.QueryRow(`SELECT 'AddressesDeviceIDAddressIndex'::regclass`)
-	if err = row.Scan(&tmp); err != nil {
-		_, err = db.Exec(`CREATE INDEX AddressesDeviceIDAddressIndex ON Addresses (DeviceID, Address)`)
-	}
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func postgresCompile(db *sql.DB) (map[string]*sql.Stmt, error) {
-	stmts := map[string]string{
-		"cleanAddress":  "DELETE FROM Addresses WHERE Seen < now() - '2 hour'::INTERVAL",
-		"cleanDevice":   fmt.Sprintf("DELETE FROM Devices WHERE Seen < now() - '%d hour'::INTERVAL", maxDeviceAge/3600),
-		"countAddress":  "SELECT count(*) FROM Addresses",
-		"countDevice":   "SELECT count(*) FROM Devices",
-		"insertAddress": "INSERT INTO Addresses (DeviceID, Seen, Address) VALUES ($1, now(), $2)",
-		"insertDevice":  "INSERT INTO Devices (DeviceID, Seen) VALUES ($1, now())",
-		"selectAddress": "SELECT Address FROM Addresses WHERE DeviceID=$1 AND Seen > now() - '1 hour'::INTERVAL ORDER BY random() LIMIT 16",
-		"selectDevice":  "SELECT Seen FROM Devices WHERE DeviceID=$1",
-		"updateAddress": "UPDATE Addresses SET Seen=now() WHERE DeviceID=$1 AND Address=$2",
-		"updateDevice":  "UPDATE Devices SET Seen=now() WHERE DeviceID=$1",
-	}
-
-	res := make(map[string]*sql.Stmt, len(stmts))
-	for key, stmt := range stmts {
-		prep, err := db.Prepare(stmt)
-		if err != nil {
-			return nil, err
-		}
-		res[key] = prep
-	}
-	return res, nil
-}
--- a/cmd/stdiscosrv/ql.go
+++ b/cmd/stdiscosrv/ql.go
@@ -1,81 +0,0 @@
-// Copyright (C) 2015 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
-
-package main
-
-import (
-	"database/sql"
-	"fmt"
-	"log"
-
-	"github.com/cznic/ql"
-)
-
-func init() {
-	ql.RegisterDriver()
-	register("ql", qlSetup, qlCompile)
-}
-
-func qlSetup(db *sql.DB) (err error) {
-	tx, err := db.Begin()
-	if err != nil {
-		return
-	}
-
-	defer func() {
-		if err == nil {
-			err = tx.Commit()
-		} else {
-			tx.Rollback()
-		}
-	}()
-
-	_, err = tx.Exec(`CREATE TABLE IF NOT EXISTS Devices (
-		DeviceID STRING NOT NULL,
-		Seen TIME NOT NULL
-	)`)
-	if err != nil {
-		return
-	}
-
-	if _, err = tx.Exec(`CREATE INDEX IF NOT EXISTS DevicesDeviceIDIndex ON Devices (DeviceID)`); err != nil {
-		return
-	}
-
-	_, err = tx.Exec(`CREATE TABLE IF NOT EXISTS Addresses (
-		DeviceID STRING NOT NULL,
-		Seen TIME NOT NULL,
-		Address STRING NOT NULL,
-	)`)
-	if err != nil {
-		return
-	}
-
-	_, err = tx.Exec(`CREATE INDEX IF NOT EXISTS AddressesDeviceIDAddressIndex ON Addresses (DeviceID, Address)`)
-	return
-}
-
-func qlCompile(db *sql.DB) (map[string]*sql.Stmt, error) {
-	stmts := map[string]string{
-		"cleanAddress":  `DELETE FROM Addresses WHERE Seen < now() - duration("2h")`,
-		"cleanDevice":   fmt.Sprintf(`DELETE FROM Devices WHERE Seen < now() - duration("%dh")`, maxDeviceAge/3600),
-		"countAddress":  "SELECT count(*) FROM Addresses",
-		"countDevice":   "SELECT count(*) FROM Devices",
-		"insertAddress": "INSERT INTO Addresses (DeviceID, Seen, Address) VALUES ($1, now(), $2)",
-		"insertDevice":  "INSERT INTO Devices (DeviceID, Seen) VALUES ($1, now())",
-		"selectAddress": `SELECT Address from Addresses WHERE DeviceID==$1 AND Seen > now() - duration("1h") LIMIT 16`,
-		"selectDevice":  "SELECT Seen FROM Devices WHERE DeviceID==$1",
-		"updateAddress": "UPDATE Addresses Seen=now() WHERE DeviceID==$1 AND Address==$2",
-		"updateDevice":  "UPDATE Devices Seen=now() WHERE DeviceID==$1",
-	}
-
-	res := make(map[string]*sql.Stmt, len(stmts))
-	for key, stmt := range stmts {
-		prep, err := db.Prepare(stmt)
-		if err != nil {
-			log.Println("Failed to compile", stmt)
-			return nil, err
-		}
-		res[key] = prep
-	}
-	return res, nil
-}
--- a/cmd/stdiscosrv/querysrv.go
+++ b/cmd/stdiscosrv/querysrv.go
@@ -1,492 +0,0 @@
-// Copyright (C) 2014-2015 Jakob Borg and Contributors (see the CONTRIBUTORS file).
-
-package main
-
-import (
-	"bytes"
-	"crypto/tls"
-	"database/sql"
-	"encoding/json"
-	"encoding/pem"
-	"fmt"
-	"log"
-	"math/rand"
-	"net"
-	"net/http"
-	"net/url"
-	"strconv"
-	"sync"
-	"time"
-
-	"github.com/golang/groupcache/lru"
-	"github.com/syncthing/syncthing/lib/protocol"
-	"golang.org/x/net/context"
-	"golang.org/x/time/rate"
-)
-
-type querysrv struct {
-	addr     string
-	db       *sql.DB
-	prep     map[string]*sql.Stmt
-	limiter  *safeCache
-	cert     tls.Certificate
-	listener net.Listener
-}
-
-type announcement struct {
-	Seen      time.Time `json:"seen"`
-	Addresses []string  `json:"addresses"`
-}
-
-type safeCache struct {
-	*lru.Cache
-	mut sync.Mutex
-}
-
-func (s *safeCache) Get(key string) (val interface{}, ok bool) {
-	s.mut.Lock()
-	val, ok = s.Cache.Get(key)
-	s.mut.Unlock()
-	return
-}
-
-func (s *safeCache) Add(key string, val interface{}) {
-	s.mut.Lock()
-	s.Cache.Add(key, val)
-	s.mut.Unlock()
-}
-
-type requestID int64
-
-func (i requestID) String() string {
-	return fmt.Sprintf("%016x", int64(i))
-}
-
-type contextKey int
-
-const idKey contextKey = iota
-
-func negCacheFor(lastSeen time.Time) int {
-	since := time.Since(lastSeen).Seconds()
-	if since >= maxDeviceAge {
-		return maxNegCache
-	}
-	if since < 0 {
-		// That's weird
-		return minNegCache
-	}
-
-	// Return a value linearly scaled from minNegCache (at zero seconds ago)
-	// to maxNegCache (at maxDeviceAge seconds ago).
-	r := since / maxDeviceAge
-	return int(minNegCache + r*(maxNegCache-minNegCache))
-}
-
-func (s *querysrv) Serve() {
-	s.limiter = &safeCache{
-		Cache: lru.New(lruSize),
-	}
-
-	if useHTTP {
-		listener, err := net.Listen("tcp", s.addr)
-		if err != nil {
-			log.Println("Listen:", err)
-			return
-		}
-		s.listener = listener
-	} else {
-		tlsCfg := &tls.Config{
-			Certificates:           []tls.Certificate{s.cert},
-			ClientAuth:             tls.RequestClientCert,
-			SessionTicketsDisabled: true,
-			MinVersion:             tls.VersionTLS12,
-			CipherSuites: []uint16{
-				tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
-				tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
-				tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
-				tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
-				tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
-				tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
-			},
-		}
-
-		tlsListener, err := tls.Listen("tcp", s.addr, tlsCfg)
-		if err != nil {
-			log.Println("Listen:", err)
-			return
-		}
-		s.listener = tlsListener
-	}
-
-	http.HandleFunc("/v2/", s.handler)
-	http.HandleFunc("/ping", handlePing)
-
-	srv := &http.Server{
-		ReadTimeout:    5 * time.Second,
-		WriteTimeout:   5 * time.Second,
-		MaxHeaderBytes: 1 << 10,
-	}
-
-	if err := srv.Serve(s.listener); err != nil {
-		log.Println("Serve:", err)
-	}
-}
-
-var topCtx = context.Background()
-
-func (s *querysrv) handler(w http.ResponseWriter, req *http.Request) {
-	reqID := requestID(rand.Int63())
-	ctx := context.WithValue(topCtx, idKey, reqID)
-
-	if debug {
-		log.Println(reqID, req.Method, req.URL)
-	}
-
-	t0 := time.Now()
-	defer func() {
-		diff := time.Since(t0)
-		var comment string
-		if diff > time.Second {
-			comment = "(very slow request)"
-		} else if diff > 100*time.Millisecond {
-			comment = "(slow request)"
-		}
-		if comment != "" || debug {
-			log.Println(reqID, req.Method, req.URL, "completed in", diff, comment)
-		}
-	}()
-
-	var remoteIP net.IP
-	if useHTTP {
-		remoteIP = net.ParseIP(req.Header.Get("X-Forwarded-For"))
-	} else {
-		addr, err := net.ResolveTCPAddr("tcp", req.RemoteAddr)
-		if err != nil {
-			log.Println("remoteAddr:", err)
-			http.Error(w, "Internal Server Error", http.StatusInternalServerError)
-			return
-		}
-		remoteIP = addr.IP
-	}
-
-	if s.limit(remoteIP) {
-		if debug {
-			log.Println(remoteIP, "is limited")
-		}
-		w.Header().Set("Retry-After", "60")
-		http.Error(w, "Too Many Requests", 429)
-		return
-	}
-
-	switch req.Method {
-	case "GET":
-		s.handleGET(ctx, w, req)
-	case "POST":
-		s.handlePOST(ctx, remoteIP, w, req)
-	default:
-		globalStats.Error()
-		http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
-	}
-}
-
-func (s *querysrv) handleGET(ctx context.Context, w http.ResponseWriter, req *http.Request) {
-	reqID := ctx.Value(idKey).(requestID)
-
-	deviceID, err := protocol.DeviceIDFromString(req.URL.Query().Get("device"))
-	if err != nil {
-		if debug {
-			log.Println(reqID, "bad device param")
-		}
-		globalStats.Error()
-		http.Error(w, "Bad Request", http.StatusBadRequest)
-		return
-	}
-
-	var ann announcement
-
-	ann.Seen, err = s.getDeviceSeen(deviceID)
-	negCache := strconv.Itoa(negCacheFor(ann.Seen))
-	w.Header().Set("Retry-After", negCache)
-	w.Header().Set("Cache-Control", "public, max-age="+negCache)
-
-	if err != nil {
-		// The device is not in the database.
-		globalStats.Query()
-		http.Error(w, "Not Found", http.StatusNotFound)
-		return
-	}
-
-	t0 := time.Now()
-	ann.Addresses, err = s.getAddresses(ctx, deviceID)
-	if err != nil {
-		log.Println(reqID, "getAddresses:", err)
-		globalStats.Error()
-		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
-		return
-	}
-	if debug {
-		log.Println(reqID, "getAddresses in", time.Since(t0))
-	}
-
-	globalStats.Query()
-
-	if len(ann.Addresses) == 0 {
-		http.Error(w, "Not Found", http.StatusNotFound)
-		return
-	}
-
-	globalStats.Answer()
-
-	w.Header().Set("Content-Type", "application/json")
-	json.NewEncoder(w).Encode(ann)
-}
-
-func (s *querysrv) handlePOST(ctx context.Context, remoteIP net.IP, w http.ResponseWriter, req *http.Request) {
-	reqID := ctx.Value(idKey).(requestID)
-
-	rawCert := certificateBytes(req)
-	if rawCert == nil {
-		if debug {
-			log.Println(reqID, "no certificates")
-		}
-		globalStats.Error()
-		http.Error(w, "Forbidden", http.StatusForbidden)
-		return
-	}
-
-	var ann announcement
-	if err := json.NewDecoder(req.Body).Decode(&ann); err != nil {
-		if debug {
-			log.Println(reqID, "decode:", err)
-		}
-		globalStats.Error()
-		http.Error(w, "Bad Request", http.StatusBadRequest)
-		return
-	}
-
-	deviceID := protocol.NewDeviceID(rawCert)
-
-	// handleAnnounce returns *two* errors. The first indicates a problem with
-	// something the client posted to us. We should return a 400 Bad Request
-	// and not worry about it. The second indicates that the request was fine,
-	// but something internal messed up. We should log it and respond with a
-	// more apologetic 500 Internal Server Error.
-	userErr, internalErr := s.handleAnnounce(ctx, remoteIP, deviceID, ann.Addresses)
-	if userErr != nil {
-		if debug {
-			log.Println(reqID, "handleAnnounce:", userErr)
-		}
-		globalStats.Error()
-		http.Error(w, "Bad Request", http.StatusBadRequest)
-		return
-	}
-	if internalErr != nil {
-		log.Println(reqID, "handleAnnounce:", internalErr)
-		globalStats.Error()
-		http.Error(w, "Internal Server Error", http.StatusInternalServerError)
-		return
-	}
-
-	globalStats.Announce()
-
-	// TODO: Slowly increase this for stable clients
-	w.Header().Set("Reannounce-After", "1800")
-
-	// We could return the lookup result here, but it's kind of unnecessarily
-	// expensive to go query the database again so we let the client decide to
-	// do a lookup if they really care.
-	w.WriteHeader(http.StatusNoContent)
-}
-
-func (s *querysrv) Stop() {
-	s.listener.Close()
-}
-
-func (s *querysrv) handleAnnounce(ctx context.Context, remote net.IP, deviceID protocol.DeviceID, addresses []string) (userErr, internalErr error) {
-	reqID := ctx.Value(idKey).(requestID)
-
-	tx, err := s.db.Begin()
-	if err != nil {
-		internalErr = err
-		return
-	}
-
-	defer func() {
-		// Since we return from a bunch of different places, we handle
-		// rollback in the defer.
-		if internalErr != nil || userErr != nil {
-			tx.Rollback()
-		}
-	}()
-
-	for _, annAddr := range addresses {
-		uri, err := url.Parse(annAddr)
-		if err != nil {
-			userErr = err
-			return
-		}
-
-		host, port, err := net.SplitHostPort(uri.Host)
-		if err != nil {
-			userErr = err
-			return
-		}
-
-		ip := net.ParseIP(host)
-		if host == "" || ip.IsUnspecified() {
-			// Do not use IPv6 remote address if requested scheme is tcp4
-			if uri.Scheme == "tcp4" && remote.To4() == nil {
-				continue
-			}
-
-			// Do not use IPv4 remote address if requested scheme is tcp6
-			if uri.Scheme == "tcp6" && remote.To4() != nil {
-				continue
-			}
-
-			host = remote.String()
-		}
-
-		uri.Host = net.JoinHostPort(host, port)
-
-		if err := s.updateAddress(ctx, tx, deviceID, uri.String()); err != nil {
-			internalErr = err
-			return
-		}
-	}
-
-	if err := s.updateDevice(ctx, tx, deviceID); err != nil {
-		internalErr = err
-		return
-	}
-
-	t0 := time.Now()
-	internalErr = tx.Commit()
-	if debug {
-		log.Println(reqID, "commit in", time.Since(t0))
-	}
-	return
-}
-
-func (s *querysrv) limit(remote net.IP) bool {
-	key := remote.String()
-
-	bkt, ok := s.limiter.Get(key)
-	if ok {
-		bkt := bkt.(*rate.Limiter)
-		if !bkt.Allow() {
-			// Rate limit exceeded; ignore packet
-			return true
-		}
-	} else {
-		// limitAvg is in packets per ten seconds.
-		s.limiter.Add(key, rate.NewLimiter(rate.Limit(limitAvg)/10, limitBurst))
-	}
-
-	return false
-}
-
-func (s *querysrv) updateDevice(ctx context.Context, tx *sql.Tx, device protocol.DeviceID) error {
-	reqID := ctx.Value(idKey).(requestID)
-	t0 := time.Now()
-	res, err := tx.Stmt(s.prep["updateDevice"]).Exec(device.String())
-	if err != nil {
-		return err
-	}
-	if debug {
-		log.Println(reqID, "updateDevice in", time.Since(t0))
-	}
-
-	if rows, _ := res.RowsAffected(); rows == 0 {
-		t0 = time.Now()
-		_, err := tx.Stmt(s.prep["insertDevice"]).Exec(device.String())
-		if err != nil {
-			return err
-		}
-		if debug {
-			log.Println(reqID, "insertDevice in", time.Since(t0))
-		}
-	}
-
-	return nil
-}
-
-func (s *querysrv) updateAddress(ctx context.Context, tx *sql.Tx, device protocol.DeviceID, uri string) error {
-	res, err := tx.Stmt(s.prep["updateAddress"]).Exec(device.String(), uri)
-	if err != nil {
-		return err
-	}
-
-	if rows, _ := res.RowsAffected(); rows == 0 {
-		_, err := tx.Stmt(s.prep["insertAddress"]).Exec(device.String(), uri)
-		if err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-func (s *querysrv) getAddresses(ctx context.Context, device protocol.DeviceID) ([]string, error) {
-	rows, err := s.prep["selectAddress"].Query(device.String())
-	if err != nil {
-		return nil, err
-	}
-	defer rows.Close()
-
-	var res []string
-	for rows.Next() {
-		var addr string
-
-		err := rows.Scan(&addr)
-		if err != nil {
-			log.Println("Scan:", err)
-			continue
-		}
-		res = append(res, addr)
-	}
-
-	return res, nil
-}
-
-func (s *querysrv) getDeviceSeen(device protocol.DeviceID) (time.Time, error) {
-	row := s.prep["selectDevice"].QueryRow(device.String())
-	var seen time.Time
-	if err := row.Scan(&seen); err != nil {
-		return time.Time{}, err
-	}
-	return seen.In(time.UTC), nil
-}
-
-func handlePing(w http.ResponseWriter, r *http.Request) {
-	w.WriteHeader(204)
-}
-
-func certificateBytes(req *http.Request) []byte {
-	if req.TLS != nil && len(req.TLS.PeerCertificates) > 0 {
-		return req.TLS.PeerCertificates[0].Raw
-	}
-
-	if hdr := req.Header.Get("X-SSL-Cert"); hdr != "" {
-		bs := []byte(hdr)
-		// The certificate is in PEM format but with spaces for newlines. We
-		// need to reinstate the newlines for the PEM decoder. But we need to
-		// leave the spaces in the BEGIN and END lines - the first and last
-		// space - alone.
-		firstSpace := bytes.Index(bs, []byte(" "))
-		lastSpace := bytes.LastIndex(bs, []byte(" "))
-		for i := firstSpace + 1; i < lastSpace; i++ {
-			if bs[i] == ' ' {
-				bs[i] = '\n'
-			}
-		}
-		block, _ := pem.Decode(bs)
-		if block == nil {
-			// Decoding failed
-			return nil
-		}
-		return block.Bytes
-	}
-
-	return nil
-}
--- a/cmd/stdiscosrv/replication.go
+++ b/cmd/stdiscosrv/replication.go
@@ -0,0 +1,326 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"crypto/tls"
+	"encoding/binary"
+	"fmt"
+	io "io"
+	"log"
+	"net"
+	"time"
+
+	"github.com/syncthing/syncthing/lib/protocol"
+)
+
+const replicationReadTimeout = time.Minute
+const replicationHeartbeatInterval = time.Second * 30
+
+type replicator interface {
+	send(key string, addrs []DatabaseAddress, seen int64)
+}
+
+// a replicationSender tries to connect to the remote address and provide
+// them with a feed of replication updates.
+type replicationSender struct {
+	dst        string
+	cert       tls.Certificate // our certificate
+	allowedIDs []protocol.DeviceID
+	outbox     chan ReplicationRecord
+	stop       chan struct{}
+}
+
+func newReplicationSender(dst string, cert tls.Certificate, allowedIDs []protocol.DeviceID) *replicationSender {
+	return &replicationSender{
+		dst:        dst,
+		cert:       cert,
+		allowedIDs: allowedIDs,
+		outbox:     make(chan ReplicationRecord, replicationOutboxSize),
+		stop:       make(chan struct{}),
+	}
+}
+
+func (s *replicationSender) Serve() {
+	// Sleep a little at startup. Peers often restart at the same time, and
+	// this avoid the service failing and entering backoff state
+	// unnecessarily, while also reducing the reconnect rate to something
+	// reasonable by default.
+	time.Sleep(2 * time.Second)
+
+	tlsCfg := &tls.Config{
+		Certificates:       []tls.Certificate{s.cert},
+		MinVersion:         tls.VersionTLS12,
+		InsecureSkipVerify: true,
+	}
+
+	// Dial the TLS connection.
+	conn, err := tls.Dial("tcp", s.dst, tlsCfg)
+	if err != nil {
+		log.Println("Replication connect:", err)
+		return
+	}
+	defer func() {
+		conn.SetWriteDeadline(time.Now().Add(time.Second))
+		conn.Close()
+	}()
+
+	// Get the other side device ID.
+	remoteID, err := deviceID(conn)
+	if err != nil {
+		log.Println("Replication connect:", err)
+		return
+	}
+
+	// Verify it's in the set of allowed device IDs.
+	if !deviceIDIn(remoteID, s.allowedIDs) {
+		log.Println("Replication connect: unexpected device ID:", remoteID)
+		return
+	}
+
+	heartBeatTicker := time.NewTicker(replicationHeartbeatInterval)
+	defer heartBeatTicker.Stop()
+
+	// Send records.
+	buf := make([]byte, 1024)
+	for {
+		select {
+		case <-heartBeatTicker.C:
+			if len(s.outbox) > 0 {
+				// No need to send heartbeats if there are events/prevrious
+				// heartbeats to send, they will keep the connection alive.
+				continue
+			}
+			// Empty replication message is the heartbeat:
+			s.outbox <- ReplicationRecord{}
+
+		case rec := <-s.outbox:
+			// Buffer must hold record plus four bytes for size
+			size := rec.Size()
+			if len(buf) < size+4 {
+				buf = make([]byte, size+4)
+			}
+
+			// Record comes after the four bytes size
+			n, err := rec.MarshalTo(buf[4:])
+			if err != nil {
+				// odd to get an error here, but we haven't sent anything
+				// yet so it's not fatal
+				replicationSendsTotal.WithLabelValues("error").Inc()
+				log.Println("Replication marshal:", err)
+				continue
+			}
+			binary.BigEndian.PutUint32(buf, uint32(n))
+
+			// Send
+			conn.SetWriteDeadline(time.Now().Add(5 * time.Second))
+			if _, err := conn.Write(buf[:4+n]); err != nil {
+				replicationSendsTotal.WithLabelValues("error").Inc()
+				log.Println("Replication write:", err)
+				// Yes, we are loosing the replication event here.
+				return
+			}
+			replicationSendsTotal.WithLabelValues("success").Inc()
+
+		case <-s.stop:
+			return
+		}
+	}
+}
+
+func (s *replicationSender) Stop() {
+	close(s.stop)
+}
+
+func (s *replicationSender) String() string {
+	return fmt.Sprintf("replicationSender(%q)", s.dst)
+}
+
+func (s *replicationSender) send(key string, ps []DatabaseAddress, seen int64) {
+	item := ReplicationRecord{
+		Key:       key,
+		Addresses: ps,
+	}
+
+	// The send should never block. The inbox is suitably buffered for at
+	// least a few seconds of stalls, which shouldn't happen in practice.
+	select {
+	case s.outbox <- item:
+	default:
+		replicationSendsTotal.WithLabelValues("drop").Inc()
+	}
+}
+
+// a replicationMultiplexer sends to multiple replicators
+type replicationMultiplexer []replicator
+
+func (m replicationMultiplexer) send(key string, ps []DatabaseAddress, seen int64) {
+	for _, s := range m {
+		// each send is nonblocking
+		s.send(key, ps, seen)
+	}
+}
+
+// replicationListener accepts incoming connections and reads replication
+// items from them. Incoming items are applied to the KV store.
+type replicationListener struct {
+	addr       string
+	cert       tls.Certificate
+	allowedIDs []protocol.DeviceID
+	db         database
+	stop       chan struct{}
+}
+
+func newReplicationListener(addr string, cert tls.Certificate, allowedIDs []protocol.DeviceID, db database) *replicationListener {
+	return &replicationListener{
+		addr:       addr,
+		cert:       cert,
+		allowedIDs: allowedIDs,
+		db:         db,
+		stop:       make(chan struct{}),
+	}
+}
+
+func (l *replicationListener) Serve() {
+	tlsCfg := &tls.Config{
+		Certificates:       []tls.Certificate{l.cert},
+		ClientAuth:         tls.RequestClientCert,
+		MinVersion:         tls.VersionTLS12,
+		InsecureSkipVerify: true,
+	}
+
+	lst, err := tls.Listen("tcp", l.addr, tlsCfg)
+	if err != nil {
+		log.Println("Replication listen:", err)
+		return
+	}
+	defer lst.Close()
+
+	for {
+		select {
+		case <-l.stop:
+			return
+		default:
+		}
+
+		// Accept a connection
+		conn, err := lst.Accept()
+		if err != nil {
+			log.Println("Replication accept:", err)
+			return
+		}
+
+		// Figure out the other side device ID
+		remoteID, err := deviceID(conn.(*tls.Conn))
+		if err != nil {
+			log.Println("Replication accept:", err)
+			conn.SetWriteDeadline(time.Now().Add(time.Second))
+			conn.Close()
+			continue
+		}
+
+		// Verify it is in the set of allowed device IDs
+		if !deviceIDIn(remoteID, l.allowedIDs) {
+			log.Println("Replication accept: unexpected device ID:", remoteID)
+			conn.SetWriteDeadline(time.Now().Add(time.Second))
+			conn.Close()
+			continue
+		}
+
+		go l.handle(conn)
+	}
+}
+
+func (l *replicationListener) Stop() {
+	close(l.stop)
+}
+
+func (l *replicationListener) String() string {
+	return fmt.Sprintf("replicationListener(%q)", l.addr)
+}
+
+func (l *replicationListener) handle(conn net.Conn) {
+	defer func() {
+		conn.SetWriteDeadline(time.Now().Add(time.Second))
+		conn.Close()
+	}()
+
+	buf := make([]byte, 1024)
+
+	for {
+		select {
+		case <-l.stop:
+			return
+		default:
+		}
+
+		conn.SetReadDeadline(time.Now().Add(replicationReadTimeout))
+
+		// First four bytes are the size
+		if _, err := io.ReadFull(conn, buf[:4]); err != nil {
+			log.Println("Replication read size:", err)
+			replicationRecvsTotal.WithLabelValues("error").Inc()
+			return
+		}
+
+		// Read the rest of the record
+		size := int(binary.BigEndian.Uint32(buf[:4]))
+		if len(buf) < size {
+			buf = make([]byte, size)
+		}
+
+		if size == 0 {
+			// Heartbeat, ignore
+			continue
+		}
+
+		if _, err := io.ReadFull(conn, buf[:size]); err != nil {
+			log.Println("Replication read record:", err)
+			replicationRecvsTotal.WithLabelValues("error").Inc()
+			return
+		}
+
+		// Unmarshal
+		var rec ReplicationRecord
+		if err := rec.Unmarshal(buf[:size]); err != nil {
+			log.Println("Replication unmarshal:", err)
+			replicationRecvsTotal.WithLabelValues("error").Inc()
+			continue
+		}
+
+		// Store
+		l.db.merge(rec.Key, rec.Addresses, rec.Seen)
+		replicationRecvsTotal.WithLabelValues("success").Inc()
+	}
+}
+
+func deviceID(conn *tls.Conn) (protocol.DeviceID, error) {
+	// Handshake may not be complete on the server side yet, which we need
+	// to get the client certificate.
+	if !conn.ConnectionState().HandshakeComplete {
+		if err := conn.Handshake(); err != nil {
+			return protocol.DeviceID{}, err
+		}
+	}
+
+	// We expect exactly one certificate.
+	certs := conn.ConnectionState().PeerCertificates
+	if len(certs) != 1 {
+		return protocol.DeviceID{}, fmt.Errorf("unexpected number of certificates (%d != 1)", len(certs))
+	}
+
+	return protocol.NewDeviceID(certs[0].Raw), nil
+}
+
+func deviceIDIn(id protocol.DeviceID, ids []protocol.DeviceID) bool {
+	for _, candidate := range ids {
+		if id == candidate {
+			return true
+		}
+	}
+	return false
+}
--- a/cmd/stdiscosrv/stats.go
+++ b/cmd/stdiscosrv/stats.go
@@ -1,141 +1,123 @@
-// Copyright (C) 2014-2015 Jakob Borg and Contributors (see the CONTRIBUTORS file).
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.

 package main

 import (
-	"bytes"
-	"database/sql"
-	"fmt"
-	"io/ioutil"
-	"log"
 	"os"
-	"sync/atomic"
-	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
 )

-type stats struct {
-	// Incremented atomically
-	announces int64
-	queries   int64
-	answers   int64
-	errors    int64
-}
+var (
+	apiRequestsTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "syncthing",
+			Subsystem: "discovery",
+			Name:      "api_requests_total",
+			Help:      "Number of API requests.",
+		}, []string{"type", "result"})
+	apiRequestsSeconds = prometheus.NewSummaryVec(
+		prometheus.SummaryOpts{
+			Namespace:  "syncthing",
+			Subsystem:  "discovery",
+			Name:       "api_requests_seconds",
+			Help:       "Latency of API requests.",
+			Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+		}, []string{"type"})

-func (s *stats) Announce() {
-	atomic.AddInt64(&s.announces, 1)
-}
+	lookupRequestsTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "syncthing",
+			Subsystem: "discovery",
+			Name:      "lookup_requests_total",
+			Help:      "Number of lookup requests.",
+		}, []string{"result"})
+	announceRequestsTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "syncthing",
+			Subsystem: "discovery",
+			Name:      "announcement_requests_total",
+			Help:      "Number of announcement requests.",
+		}, []string{"result"})

-func (s *stats) Query() {
-	atomic.AddInt64(&s.queries, 1)
-}
+	replicationSendsTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "syncthing",
+			Subsystem: "discovery",
+			Name:      "replication_sends_total",
+			Help:      "Number of replication sends.",
+		}, []string{"result"})
+	replicationRecvsTotal = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "syncthing",
+			Subsystem: "discovery",
+			Name:      "replication_recvs_total",
+			Help:      "Number of replication receives.",
+		}, []string{"result"})

-func (s *stats) Answer() {
-	atomic.AddInt64(&s.answers, 1)
-}
+	databaseKeys = prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "syncthing",
+			Subsystem: "discovery",
+			Name:      "database_keys",
+			Help:      "Number of database keys at last count.",
+		}, []string{"category"})
+	databaseStatisticsSeconds = prometheus.NewGauge(
+		prometheus.GaugeOpts{
+			Namespace: "syncthing",
+			Subsystem: "discovery",
+			Name:      "database_statistics_seconds",
+			Help:      "Time spent running the statistics routine.",
+		})

-func (s *stats) Error() {
-	atomic.AddInt64(&s.errors, 1)
-}
+	databaseOperations = prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "syncthing",
+			Subsystem: "discovery",
+			Name:      "database_operations_total",
+			Help:      "Number of database operations.",
+		}, []string{"operation", "result"})
+	databaseOperationSeconds = prometheus.NewSummaryVec(
+		prometheus.SummaryOpts{
+			Namespace:  "syncthing",
+			Subsystem:  "discovery",
+			Name:       "database_operation_seconds",
+			Help:       "Latency of database operations.",
+			Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+		}, []string{"operation"})
+)

-// Reset returns a copy of the current stats and resets the counters to
-// zero.
-func (s *stats) Reset() stats {
-	// Create a copy of the stats using atomic reads
-	copy := stats{
-		announces: atomic.LoadInt64(&s.announces),
-		queries:   atomic.LoadInt64(&s.queries),
-		answers:   atomic.LoadInt64(&s.answers),
-		errors:    atomic.LoadInt64(&s.errors),
+const (
+	dbOpGet             = "get"
+	dbOpPut             = "put"
+	dbOpMerge           = "merge"
+	dbOpDelete          = "delete"
+	dbResSuccess        = "success"
+	dbResNotFound       = "not_found"
+	dbResError          = "error"
+	dbResUnmarshalError = "unmarsh_err"
+)
+
+func init() {
+	prometheus.MustRegister(apiRequestsTotal, apiRequestsSeconds,
+		lookupRequestsTotal, announceRequestsTotal,
+		replicationSendsTotal, replicationRecvsTotal,
+		databaseKeys, databaseStatisticsSeconds,
+		databaseOperations, databaseOperationSeconds)
+
+	processCollectorOpts := prometheus.ProcessCollectorOpts{
+		Namespace: "syncthing_discovery",
+		PidFn: func() (int, error) {
+			return os.Getpid(), nil
+		},
 	}

-	// Reset the stats by subtracting the values that we copied
-	atomic.AddInt64(&s.announces, -copy.announces)
-	atomic.AddInt64(&s.queries, -copy.queries)
-	atomic.AddInt64(&s.answers, -copy.answers)
-	atomic.AddInt64(&s.errors, -copy.errors)
+	prometheus.MustRegister(
+		prometheus.NewProcessCollector(processCollectorOpts),
+	)

-	return copy
-}
-
-type statssrv struct {
-	intv time.Duration
-	file string
-	db   *sql.DB
-}
-
-func (s *statssrv) Serve() {
-	lastReset := time.Now()
-	for {
-		time.Sleep(next(s.intv))
-
-		stats := globalStats.Reset()
-		d := time.Since(lastReset).Seconds()
-		lastReset = time.Now()
-
-		log.Printf("Stats: %.02f announces/s, %.02f queries/s, %.02f answers/s, %.02f errors/s",
-			float64(stats.announces)/d, float64(stats.queries)/d, float64(stats.answers)/d, float64(stats.errors)/d)
-
-		if s.file != "" {
-			s.writeToFile(stats, d)
-		}
-	}
-}
-
-func (s *statssrv) Stop() {
-	panic("stop unimplemented")
-}
-
-func (s *statssrv) writeToFile(stats stats, secs float64) {
-	newLine := []byte("\n")
-
-	var addrs int
-	row := s.db.QueryRow("SELECT COUNT(*) FROM Addresses")
-	if err := row.Scan(&addrs); err != nil {
-		log.Println("stats query:", err)
-		return
-	}
-
-	fd, err := os.OpenFile(s.file, os.O_RDWR|os.O_CREATE, 0666)
-	if err != nil {
-		log.Println("stats file:", err)
-		return
-	}
-	defer func() {
-		err = fd.Close()
-		if err != nil {
-			log.Println("stats file:", err)
-		}
-	}()
-
-	bs, err := ioutil.ReadAll(fd)
-	if err != nil {
-		log.Println("stats file:", err)
-		return
-	}
-	lines := bytes.Split(bytes.TrimSpace(bs), newLine)
-	if len(lines) > 12 {
-		lines = lines[len(lines)-12:]
-	}
-
-	latest := fmt.Sprintf("%v: %6d addresses, %8.02f announces/s, %8.02f queries/s, %8.02f answers/s, %8.02f errors/s\n",
-		time.Now().UTC().Format(time.RFC3339), addrs,
-		float64(stats.announces)/secs, float64(stats.queries)/secs, float64(stats.answers)/secs, float64(stats.errors)/secs)
-	lines = append(lines, []byte(latest))
-
-	_, err = fd.Seek(0, 0)
-	if err != nil {
-		log.Println("stats file:", err)
-		return
-	}
-	err = fd.Truncate(0)
-	if err != nil {
-		log.Println("stats file:", err)
-		return
-	}
-
-	_, err = fd.Write(bytes.Join(lines, newLine))
-	if err != nil {
-		log.Println("stats file:", err)
-		return
-	}
 }
--- a/cmd/stfileinfo/main.go
+++ b/cmd/stfileinfo/main.go
@@ -68,8 +68,8 @@ func main() {
 		}

 		blockSize := int(fi.Size())
-		if *standardBlocks || blockSize < protocol.BlockSize {
-			blockSize = protocol.BlockSize
+		if *standardBlocks || blockSize < protocol.MinBlockSize {
+			blockSize = protocol.BlockSize(fi.Size())
 		}
 		bs, err := scanner.Blocks(context.TODO(), fd, blockSize, fi.Size(), nil, true)
 		if err != nil {
--- a/cmd/stfindignored/main.go
+++ b/cmd/stfindignored/main.go
@@ -0,0 +1,44 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+// Commmand stfindignored lists ignored files under a given folder root.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+
+	"github.com/syncthing/syncthing/lib/fs"
+	"github.com/syncthing/syncthing/lib/ignore"
+)
+
+func main() {
+	flag.Parse()
+	root := flag.Arg(0)
+	if root == "" {
+		root = "."
+	}
+
+	vfs := fs.NewWalkFilesystem(fs.NewFilesystem(fs.FilesystemTypeBasic, root))
+
+	ign := ignore.New(vfs)
+	if err := ign.Load(".stignore"); err != nil {
+		fmt.Fprintf(os.Stderr, "Fatal: loading ignores: %v\n", err)
+		os.Exit(1)
+	}
+
+	vfs.Walk(".", func(path string, info fs.FileInfo, err error) error {
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Warning: %s: %v\n", path, err)
+			return fs.SkipDir
+		}
+		if ign.Match(path).IsIgnored() {
+			fmt.Println(path)
+		}
+		return nil
+	})
+}
--- a/cmd/stgenfiles/main.go
+++ b/cmd/stgenfiles/main.go
@@ -82,7 +82,7 @@ func generateOneFile(fd io.ReadSeeker, p1 string, s int64) error {
 		return err
 	}

-	_ = os.Chmod(p1, os.FileMode(rand.Intn(0777)|0400))
+	os.Chmod(p1, os.FileMode(rand.Intn(0777)|0400))

 	t := time.Now().Add(-time.Duration(rand.Intn(30*86400)) * time.Second)
 	return os.Chtimes(p1, t, t)
--- a/cmd/stindex/dump.go
+++ b/cmd/stindex/dump.go
@@ -16,7 +16,7 @@ import (
 	"github.com/syncthing/syncthing/lib/protocol"
 )

-func dump(ldb *db.Instance) {
+func dump(ldb *db.Lowlevel) {
 	it := ldb.NewIterator(nil, nil)
 	for it.Next() {
 		key := it.Key()
--- a/cmd/stindex/dumpsize.go
+++ b/cmd/stindex/dumpsize.go
@@ -37,7 +37,7 @@ func (h *ElementHeap) Pop() interface{} {
 	return x
 }

-func dumpsize(ldb *db.Instance) {
+func dumpsize(ldb *db.Lowlevel) {
 	h := &ElementHeap{}
 	heap.Init(h)

--- a/cmd/stindex/idxck.go
+++ b/cmd/stindex/idxck.go
@@ -0,0 +1,242 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+
+	"github.com/syncthing/syncthing/lib/db"
+	"github.com/syncthing/syncthing/lib/protocol"
+)
+
+type fileInfoKey struct {
+	folder uint32
+	device uint32
+	name   string
+}
+
+type globalKey struct {
+	folder uint32
+	name   string
+}
+
+type sequenceKey struct {
+	folder   uint32
+	sequence uint64
+}
+
+func idxck(ldb *db.Lowlevel) (success bool) {
+	folders := make(map[uint32]string)
+	devices := make(map[uint32]string)
+	deviceToIDs := make(map[string]uint32)
+	fileInfos := make(map[fileInfoKey]protocol.FileInfo)
+	globals := make(map[globalKey]db.VersionList)
+	sequences := make(map[sequenceKey]string)
+	needs := make(map[globalKey]struct{})
+	var localDeviceKey uint32
+	success = true
+
+	it := ldb.NewIterator(nil, nil)
+	for it.Next() {
+		key := it.Key()
+		switch key[0] {
+		case db.KeyTypeDevice:
+			folder := binary.BigEndian.Uint32(key[1:])
+			device := binary.BigEndian.Uint32(key[1+4:])
+			name := nulString(key[1+4+4:])
+
+			var f protocol.FileInfo
+			err := f.Unmarshal(it.Value())
+			if err != nil {
+				fmt.Println("Unable to unmarshal FileInfo:", err)
+				success = false
+				continue
+			}
+
+			fileInfos[fileInfoKey{folder, device, name}] = f
+
+		case db.KeyTypeGlobal:
+			folder := binary.BigEndian.Uint32(key[1:])
+			name := nulString(key[1+4:])
+			var flv db.VersionList
+			if err := flv.Unmarshal(it.Value()); err != nil {
+				fmt.Println("Unable to unmarshal VersionList:", err)
+				success = false
+				continue
+			}
+			globals[globalKey{folder, name}] = flv
+
+		case db.KeyTypeFolderIdx:
+			key := binary.BigEndian.Uint32(it.Key()[1:])
+			folders[key] = string(it.Value())
+
+		case db.KeyTypeDeviceIdx:
+			key := binary.BigEndian.Uint32(it.Key()[1:])
+			devices[key] = string(it.Value())
+			deviceToIDs[string(it.Value())] = key
+			if bytes.Equal(it.Value(), protocol.LocalDeviceID[:]) {
+				localDeviceKey = key
+			}
+
+		case db.KeyTypeSequence:
+			folder := binary.BigEndian.Uint32(key[1:])
+			seq := binary.BigEndian.Uint64(key[5:])
+			val := it.Value()
+			sequences[sequenceKey{folder, seq}] = string(val[9:])
+
+		case db.KeyTypeNeed:
+			folder := binary.BigEndian.Uint32(key[1:])
+			name := nulString(key[1+4:])
+			needs[globalKey{folder, name}] = struct{}{}
+		}
+	}
+
+	if localDeviceKey == 0 {
+		fmt.Println("Missing key for local device in device index (bailing out)")
+		success = false
+		return
+	}
+
+	for fk, fi := range fileInfos {
+		if fk.name != fi.Name {
+			fmt.Printf("Mismatching FileInfo name, %q (key) != %q (actual)\n", fk.name, fi.Name)
+			success = false
+		}
+
+		folder := folders[fk.folder]
+		if folder == "" {
+			fmt.Printf("Unknown folder ID %d for FileInfo %q\n", fk.folder, fk.name)
+			success = false
+			continue
+		}
+		if devices[fk.device] == "" {
+			fmt.Printf("Unknown device ID %d for FileInfo %q, folder %q\n", fk.folder, fk.name, folder)
+			success = false
+		}
+
+		if fk.device == localDeviceKey {
+			name, ok := sequences[sequenceKey{fk.folder, uint64(fi.Sequence)}]
+			if !ok {
+				fmt.Printf("Sequence entry missing for FileInfo %q, folder %q, seq %d\n", fi.Name, folder, fi.Sequence)
+				success = false
+				continue
+			}
+			if name != fi.Name {
+				fmt.Printf("Sequence entry refers to wrong name, %q (seq) != %q (FileInfo), folder %q, seq %d\n", name, fi.Name, folder, fi.Sequence)
+				success = false
+			}
+		}
+	}
+
+	for gk, vl := range globals {
+		folder := folders[gk.folder]
+		if folder == "" {
+			fmt.Printf("Unknown folder ID %d for VersionList %q\n", gk.folder, gk.name)
+			success = false
+		}
+		for i, fv := range vl.Versions {
+			dev, ok := deviceToIDs[string(fv.Device)]
+			if !ok {
+				fmt.Printf("VersionList %q, folder %q refers to unknown device %q\n", gk.name, folder, fv.Device)
+				success = false
+			}
+			fi, ok := fileInfos[fileInfoKey{gk.folder, dev, gk.name}]
+			if !ok {
+				fmt.Printf("VersionList %q, folder %q, entry %d refers to unknown FileInfo\n", gk.name, folder, i)
+				success = false
+			}
+			if !fi.Version.Equal(fv.Version) {
+				fmt.Printf("VersionList %q, folder %q, entry %d, FileInfo version mismatch, %v (VersionList) != %v (FileInfo)\n", gk.name, folder, i, fv.Version, fi.Version)
+				success = false
+			}
+			if fi.IsInvalid() != fv.Invalid {
+				fmt.Printf("VersionList %q, folder %q, entry %d, FileInfo invalid mismatch, %v (VersionList) != %v (FileInfo)\n", gk.name, folder, i, fv.Invalid, fi.IsInvalid())
+				success = false
+			}
+		}
+
+		// If we need this file we should have a need entry for it. False
+		// positives from needsLocally for deleted files, where we might
+		// legitimately lack an entry if we never had it, and ignored files.
+		if needsLocally(vl) {
+			_, ok := needs[gk]
+			if !ok {
+				dev := deviceToIDs[string(vl.Versions[0].Device)]
+				fi := fileInfos[fileInfoKey{gk.folder, dev, gk.name}]
+				if !fi.IsDeleted() && !fi.IsIgnored() {
+					fmt.Printf("Missing need entry for needed file %q, folder %q\n", gk.name, folder)
+				}
+			}
+		}
+	}
+
+	seenSeq := make(map[fileInfoKey]uint64)
+	for sk, name := range sequences {
+		folder := folders[sk.folder]
+		if folder == "" {
+			fmt.Printf("Unknown folder ID %d for sequence entry %d, %q\n", sk.folder, sk.sequence, name)
+			success = false
+			continue
+		}
+
+		if prev, ok := seenSeq[fileInfoKey{folder: sk.folder, name: name}]; ok {
+			fmt.Printf("Duplicate sequence entry for %q, folder %q, seq %d (prev %d)\n", name, folder, sk.sequence, prev)
+			success = false
+		}
+		seenSeq[fileInfoKey{folder: sk.folder, name: name}] = sk.sequence
+
+		fi, ok := fileInfos[fileInfoKey{sk.folder, localDeviceKey, name}]
+		if !ok {
+			fmt.Printf("Missing FileInfo for sequence entry %d, folder %q, %q\n", sk.sequence, folder, name)
+			success = false
+			continue
+		}
+		if fi.Sequence != int64(sk.sequence) {
+			fmt.Printf("Sequence mismatch for %q, folder %q, %d (key) != %d (FileInfo)\n", name, folder, sk.sequence, fi.Sequence)
+			success = false
+		}
+	}
+
+	for nk := range needs {
+		folder := folders[nk.folder]
+		if folder == "" {
+			fmt.Printf("Unknown folder ID %d for need entry %q\n", nk.folder, nk.name)
+			success = false
+			continue
+		}
+
+		vl, ok := globals[nk]
+		if !ok {
+			fmt.Printf("Missing global for need entry %q, folder %q\n", nk.name, folder)
+			success = false
+			continue
+		}
+
+		if !needsLocally(vl) {
+			fmt.Printf("Need entry for file we don't need, %q, folder %q\n", nk.name, folder)
+			success = false
+		}
+	}
+
+	return
+}
+
+func needsLocally(vl db.VersionList) bool {
+	var lv *protocol.Vector
+	for _, fv := range vl.Versions {
+		if bytes.Equal(fv.Device, protocol.LocalDeviceID[:]) {
+			lv = &fv.Version
+			break
+		}
+	}
+	if lv == nil {
+		return true // proviosinally, it looks like we need the file
+	}
+	return !lv.GreaterEqual(vl.Versions[0].Version)
+}
--- a/cmd/stindex/main.go
+++ b/cmd/stindex/main.go
@@ -21,7 +21,7 @@ func main() {
 	log.SetFlags(0)
 	log.SetOutput(os.Stdout)

-	flag.StringVar(&mode, "mode", "dump", "Mode of operation: dump, dumpsize")
+	flag.StringVar(&mode, "mode", "dump", "Mode of operation: dump, dumpsize, idxck")

 	flag.Parse()

@@ -30,9 +30,7 @@ func main() {
 		path = filepath.Join(defaultConfigDir(), "index-v0.14.0.db")
 	}

-	fmt.Println("Path:", path)
-
-	ldb, err := db.Open(path)
+	ldb, err := db.OpenRO(path)
 	if err != nil {
 		log.Fatal(err)
 	}
@@ -41,6 +39,10 @@ func main() {
 		dump(ldb)
 	} else if mode == "dumpsize" {
 		dumpsize(ldb)
+	} else if mode == "idxck" {
+		if !idxck(ldb) {
+			os.Exit(1)
+		}
 	} else {
 		fmt.Println("Unknown mode")
 	}
--- a/cmd/stindex/util.go
+++ b/cmd/stindex/util.go
@@ -12,7 +12,7 @@ import (
 	"path/filepath"
 	"runtime"

-	"github.com/syncthing/syncthing/lib/osutil"
+	"github.com/syncthing/syncthing/lib/fs"
 )

 func nulString(bs []byte) string {
@@ -33,7 +33,7 @@ func defaultConfigDir() string {
 		return filepath.Join(os.Getenv("AppData"), "Syncthing")

 	case "darwin":
-		dir, err := osutil.ExpandTilde("~/Library/Application Support/Syncthing")
+		dir, err := fs.ExpandTilde("~/Library/Application Support/Syncthing")
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -43,7 +43,7 @@ func defaultConfigDir() string {
 		if xdgCfg := os.Getenv("XDG_CONFIG_HOME"); xdgCfg != "" {
 			return filepath.Join(xdgCfg, "syncthing")
 		}
-		dir, err := osutil.ExpandTilde("~/.config/syncthing")
+		dir, err := fs.ExpandTilde("~/.config/syncthing")
 		if err != nil {
 			log.Fatal(err)
 		}
--- a/cmd/strelaypoolsrv/auto/.gitignore
+++ b/cmd/strelaypoolsrv/auto/.gitignore
@@ -1 +1 @@
-gui.go
+gui.files.go
--- a/cmd/strelaypoolsrv/auto/doc.go
+++ b/cmd/strelaypoolsrv/auto/doc.go
@@ -0,0 +1,10 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+//go:generate go run ../../../script/genassets.go -o gui.files.go ../gui
+
+// Package auto contains auto generated files for web assets.
+package auto
--- a/cmd/strelaypoolsrv/gui/index.html
+++ b/cmd/strelaypoolsrv/gui/index.html
@@ -10,7 +10,7 @@

    <title>Relay stats</title>
    <link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css" rel="stylesheet"/>
-    <link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/font-awesome/4.6.1/css/font-awesome.min.css"/>
+    <link rel="stylesheet" href="//use.fontawesome.com/releases/v5.0.13/css/all.css"/>

    <style>
      #map {
@@ -56,83 +56,83 @@
            <tr>
              <th rowspan="2">Address</td>
              <th rowspan="2">
-                <a ng-click="sortType = 'status.numActiveSessions'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.numActiveSessions'; sortReverse = !sortReverse">
                  Sessions
-                  <span ng-show="sortType == 'status.numActiveSessions' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.numActiveSessions' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.numActiveSessions' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.numActiveSessions' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
              <th rowspan="2">
-                <a ng-click="sortType = 'status.numConnections'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.numConnections'; sortReverse = !sortReverse">
                  Connections
-                  <span ng-show="sortType == 'status.numConnections' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.numConnections' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.numConnections' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.numConnections' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
              <th rowspan="2">
-                <a ng-click="sortType = 'status.bytesProxied'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.bytesProxied'; sortReverse = !sortReverse">
                  Data relayed
-                  <span ng-show="sortType == 'status.bytesProxied' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.bytesProxied' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.bytesProxied' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.bytesProxied' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
              <th colspan="6" class="text-center">Transfer rate in the last period</th>
              <th rowspan="2">
-                <a ng-click="sortType = 'status.uptimeSeconds'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.uptimeSeconds'; sortReverse = !sortReverse">
                  Uptime hours
-                  <span ng-show="sortType == 'status.uptimeSeconds' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.uptimeSeconds' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.uptimeSeconds' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'status.uptimeSeconds' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
              <th rowspan="2">
-                <a ng-click="sortType = 'status.options[\'provided-by\'] || \'\''; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.options[\'provided-by\'] || \'\''; sortReverse = !sortReverse">
                  Provided by
-                  <span ng-show="sortType == 'status.options[\'provided-by\'] || \'\'' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.options[\'provided-by\'] || \'\'' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.options[\'provided-by\'] || \'\'' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.options[\'provided-by\'] || \'\'' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
            </tr>
            <tr>
              <th>
-                <a ng-click="sortType = 'status.kbps10s1m5m15m30m60m[0]'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.kbps10s1m5m15m30m60m[0]'; sortReverse = !sortReverse">
                  10s
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[0]' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[0]' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[0]' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[0]' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
              <th>
-                <a ng-click="sortType = 'status.kbps10s1m5m15m30m60m[1]'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.kbps10s1m5m15m30m60m[1]'; sortReverse = !sortReverse">
                  1m
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[1]' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[1]' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[1]' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[1]' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
              <th>
-                <a ng-click="sortType = 'status.kbps10s1m5m15m30m60m[2]'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.kbps10s1m5m15m30m60m[2]'; sortReverse = !sortReverse">
                  5m
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[2]' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[2]' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[2]' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[2]' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
              <th>
-                <a ng-click="sortType = 'status.kbps10s1m5m15m30m60m[3]'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.kbps10s1m5m15m30m60m[3]'; sortReverse = !sortReverse">
                  15m
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[3]' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[3]' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[3]' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[3]' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
              <th>
-                <a ng-click="sortType = 'status.kbps10s1m5m15m30m60m[4]'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.kbps10s1m5m15m30m60m[4]'; sortReverse = !sortReverse">
                  30m
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[4]' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[4]' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[4]' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[4]' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
              <th>
-                <a ng-click="sortType = 'status.kbps10s1m5m15m30m60m[5]'; sortReverse = !sortReverse">
+                <a ng-click="sortType = 'stats.kbps10s1m5m15m30m60m[5]'; sortReverse = !sortReverse">
                  60m
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[5]' && !sortReverse" class="fa fa-caret-down"></span>
-                  <span ng-show="sortType == 'status.kbps10s1m5m15m30m60m[5]' && sortReverse" class="fa fa-caret-up"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[5]' && !sortReverse" class="fas fa-caret-down"></span>
+                  <span ng-show="sortType == 'stats.kbps10s1m5m15m30m60m[5]' && sortReverse" class="fas fa-caret-up"></span>
                </a>
              </th>
            </tr>
@@ -140,21 +140,21 @@
          <tbody>
            <tr ng-repeat="relay in relays | orderBy:sortType:sortReverse:sortCompare" ng-mouseover="relay.showMarker()" ng-mouseleave="relay.hideMarker()">
              <td>{{ relay.address }}</td>
-              <td ng-if="relay.status === undefined" colspan="11" class="text-center">Looking up...</td>
-              <td ng-if-start="relay.status !== undefined">{{ relay.status.numActiveSessions }}</td>
-              <td>{{ relay.status.numConnections }}</td>
-              <td>{{ relay.status.bytesProxied | bytes }}</td>
-              <td>{{ relay.status.kbps10s1m5m15m30m60m[0] * 128 | bytes }}/s</td>
-              <td>{{ relay.status.kbps10s1m5m15m30m60m[1] * 128 | bytes }}/s</td>
-              <td>{{ relay.status.kbps10s1m5m15m30m60m[2] * 128 | bytes }}/s</td>
-              <td>{{ relay.status.kbps10s1m5m15m30m60m[3] * 128 | bytes }}/s</td>
-              <td>{{ relay.status.kbps10s1m5m15m30m60m[4] * 128 | bytes }}/s</td>
-              <td>{{ relay.status.kbps10s1m5m15m30m60m[5] * 128 | bytes }}/s</td>
-              <td ng-if="relay.status.uptimeSeconds != undefined">{{ relay.status.uptimeSeconds/60/60 | number:0 }}</td>
-              <td ng-if="relay.status.uptimeSeconds == undefined"></td>
-              <td title="{{ relay.status.options['provided-by'] || '' }}" ng-if-end>
-                {{ relay.status.options['provided-by'] || '' | limitTo:50 }}
-                <span ng-if="(relay.status.options['provided-by'] || '').length > 50">&hellip;
+              <td ng-if="!relay.stats" colspan="11"></td>
+              <td ng-if-start="relay.stats">{{ relay.stats.numActiveSessions }}</td>
+              <td>{{ relay.stats.numConnections }}</td>
+              <td>{{ relay.stats.bytesProxied | bytes }}</td>
+              <td>{{ relay.stats.kbps10s1m5m15m30m60m[0] * 128 | bytes }}/s</td>
+              <td>{{ relay.stats.kbps10s1m5m15m30m60m[1] * 128 | bytes }}/s</td>
+              <td>{{ relay.stats.kbps10s1m5m15m30m60m[2] * 128 | bytes }}/s</td>
+              <td>{{ relay.stats.kbps10s1m5m15m30m60m[3] * 128 | bytes }}/s</td>
+              <td>{{ relay.stats.kbps10s1m5m15m30m60m[4] * 128 | bytes }}/s</td>
+              <td>{{ relay.stats.kbps10s1m5m15m30m60m[5] * 128 | bytes }}/s</td>
+              <td ng-if="relay.stats.uptimeSeconds != undefined">{{ relay.stats.uptimeSeconds/60/60 | number:0 }}</td>
+              <td ng-if="relay.stats.uptimeSeconds == undefined"></td>
+              <td title="{{ relay.stats.options['provided-by'] || '' }}" ng-if-end>
+                {{ relay.stats.options['provided-by'] || '' | limitTo:50 }}
+                <span ng-if="(relay.stats.options['provided-by'] || '').length > 50">&hellip;
              </td>
            </tr>
          </tbody>
@@ -187,7 +187,7 @@
    <script type="text/javascript" src="//code.jquery.com/jquery-2.1.4.min.js"></script>
    <script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/angular.js/1.5.8/angular.min.js"></script>
    <script type="text/javascript" src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
-    <script type="text/javascript" src="//maps.googleapis.com/maps/api/js"></script>
+    <script type="text/javascript" src="//maps.googleapis.com/maps/api/js?key=AIzaSyDk5WJ8s7ueLKb99X5DbQ-vkWtPDAKqYs0"></script>
  </body>

  <script>
@@ -235,16 +235,16 @@
    $scope.mapBounds = new google.maps.LatLngBounds();
    $scope.tooltipTemplate = $('#infoTemplate').html();
    $scope.usedLocations = {};
-    $scope.sortType = 'status.numActiveSessions';
+    $scope.sortType = 'stats.numActiveSessions';
    $scope.sortReverse = true;
    $scope.sortCompare = function(a, b) {
      if (a.value == b.value) {
        return 0;
      }
-      if (a.type == "undefined") {
+      if (a.type == "undefined" || a.type == "null") {
        return -1;
      }
-      if (b.type == "undefined") {
+      if (b.type == "undefined" || b.type == "null") {
        return 1;
      }
      return a.value > b.value ? 1 : -1;
@@ -252,25 +252,31 @@

    $http.get("/endpoint").then(function(response) {
      $scope.relays = response.data.relays;
-      var promises = [];
-      angular.forEach($scope.relays, function(relay) {

+      angular.forEach($scope.relays, function(relay) {
        relay.uri = constructURI(relay.url);
        relay.address = relay.url.split('/')[2];

        addMarkerToMap(relay);

-        promises.push(getRelayStatus(relay));
+        if (relay.stats) {
+          angular.forEach($scope.totals, function(value, key) {
+            if (typeof $scope.totals[key] == 'number') {
+              $scope.totals[key] += relay.stats[key];
+            } else if (typeof $scope.totals[key] == 'object' && $scope.totals[key] instanceof Array) {
+              angular.forEach($scope.totals[key], function(value, index) {
+                $scope.totals[key][index] += relay.stats[key][index];
+              });
+            }
+          });
+        }
      });

-      // Can only add circles once we know the totals for transfers, which means
-      // we need to resolve all statuses.
-      $q.all(promises).then(function() {
-        angular.forEach($scope.relays, function(relay) {
-          if (relay.status) {
-            addCircleToMap(relay);
-          }
-        });
+      // After the totals were calculated, add circles.
+      angular.forEach($scope.relays, function(relay) {
+        if (relay.stats) {
+          addCircleToMap(relay);
+        }
      });

      $scope.map.fitBounds($scope.mapBounds);
@@ -330,41 +336,10 @@
        fillOpacity: 0.35,
        map: $scope.map,
        center: relay.marker.position,
-        radius: ((relay.status.bytesProxied * 100) / $scope.totals.bytesProxied) * 10000
+        radius: ((relay.stats.bytesProxied * 100) / $scope.totals.bytesProxied) * 10000
      });
    }

-    function getRelayStatus(relay) {
-      // Normal timeout doesn't deal with relays which accept the TCP connection
-      // but don't respond (some firewalls do that), so deal with it this way.
-      var timeoutRequest = $q.defer();
-      var resolveStatus = $q.defer();
-
-
-      $http.get("http://" + relay.uri.hostname + ':' + ((relay.uri.args.statusAddr && relay.uri.args.statusAddr.split(':')[1]) || "22070") + "/status", { timeout: timeoutRequest.promise }).then(function (response) {
-        relay.status = response.data;
-        resolveStatus.resolve();
-        angular.forEach($scope.totals, function(value, key) {
-          if (typeof $scope.totals[key] == 'number') {
-            $scope.totals[key] += response.data[key];
-          } else if (typeof $scope.totals[key] == 'object' && $scope.totals[key] instanceof Array) {
-            angular.forEach($scope.totals[key], function(value, index) {
-              $scope.totals[key][index] += response.data[key][index];
-            });
-          }
-        });
-      }, function() {
-        relay.status = null;
-        resolveStatus.resolve();
-      });
-
-      $timeout(function() {
-        timeoutRequest.resolve();
-      }, 5000);
-
-      return resolveStatus.promise;
-    }
-
    function constructURI(url) {
      var uri = document.createElement('a');

@@ -385,25 +360,25 @@

  <script type="text/template" id="infoTemplate">
    <div>
-      <p><b>{{ relay.uri.hostname }}</b> <span ng-if="relay.status.options['provided-by']">provided by <u>{{ relay.status.options['provided-by'] }}</u></span></p>
-      <div ng-if="relay.status">
-        <span ng-if="relay.status.startTime">Start time: {{ relay.status.startTime | date:"medium" }}</br></span>
-        <span ng-if="relay.status.bytesProxied != undefined">Proxied: {{ relay.status.bytesProxied | bytes }}</br></span>
-        <span ng-if="relay.status.numActiveSessions != undefined">Sessions: {{ relay.status.numActiveSessions }}</br></span>
-        <span ng-if="relay.status.numConnections != undefined">Clients: {{ relay.status.numConnections }}</br></span>
-        <span ng-if="relay.status.options.pools">Pools: {{ relay.status.options.pools.join(', ') }}</br></span>
-        <span ng-if="relay.status.options['global-rate'] != undefined">
-          <span ng-if="relay.status.options['global-rate'] > 0">Global rate limit: {{ relay.status.options['global-rate'] | bytes }}/s</span>
-          <span ng-if="relay.status.options['global-rate'] == 0">Global rate limit: unlimited</span>
+      <p><b>{{ relay.uri.hostname }}</b> <span ng-if="relay.stats.options['provided-by']">provided by <u>{{ relay.stats.options['provided-by'] }}</u></span></p>
+      <div ng-if="relay.stats">
+        <span ng-if="relay.stats.startTime">Start time: {{ relay.stats.startTime | date:"medium" }}</br></span>
+        <span ng-if="relay.stats.bytesProxied != undefined">Proxied: {{ relay.stats.bytesProxied | bytes }}</br></span>
+        <span ng-if="relay.stats.numActiveSessions != undefined">Sessions: {{ relay.stats.numActiveSessions }}</br></span>
+        <span ng-if="relay.stats.numConnections != undefined">Clients: {{ relay.stats.numConnections }}</br></span>
+        <span ng-if="relay.stats.options.pools">Pools: {{ relay.stats.options.pools.join(', ') }}</br></span>
+        <span ng-if="relay.stats.options['global-rate'] != undefined">
+          <span ng-if="relay.stats.options['global-rate'] > 0">Global rate limit: {{ relay.stats.options['global-rate'] | bytes }}/s</span>
+          <span ng-if="relay.stats.options['global-rate'] == 0">Global rate limit: unlimited</span>
          <br/>
        </span>
-        <span ng-if="relay.status.options['per-session-rate'] != undefined">
-          <span ng-if="relay.status.options['per-session-rate'] > 0">Session rate limit: {{ relay.status.options['per-session-rate'] | bytes }}/s</span>
-          <span ng-if="relay.status.options['per-session-rate'] == 0">Session rate limit: unlimited</span>
+        <span ng-if="relay.stats.options['per-session-rate'] != undefined">
+          <span ng-if="relay.stats.options['per-session-rate'] > 0">Session rate limit: {{ relay.stats.options['per-session-rate'] | bytes }}/s</span>
+          <span ng-if="relay.stats.options['per-session-rate'] == 0">Session rate limit: unlimited</span>
          <br/>
        </span>
      </div>
-      <div ng-if="!relay.status">
+      <div ng-if="!relay.stats">
        Data unavailable.
      <div>
    </div>
--- a/cmd/strelaypoolsrv/main.go
+++ b/cmd/strelaypoolsrv/main.go
@@ -18,12 +18,16 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"os"
 	"path/filepath"
+	"strconv"
 	"strings"
 	"time"

 	"github.com/golang/groupcache/lru"
 	"github.com/oschwald/geoip2-golang"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"github.com/syncthing/syncthing/cmd/strelaypoolsrv/auto"
 	"github.com/syncthing/syncthing/lib/relay/client"
 	"github.com/syncthing/syncthing/lib/sync"
@@ -34,12 +38,42 @@ import (
 type location struct {
 	Latitude  float64 `json:"latitude"`
 	Longitude float64 `json:"longitude"`
+	City      string  `json:"city"`
+	Country   string  `json:"country"`
+	Continent string  `json:"continent"`
 }

 type relay struct {
-	URL      string   `json:"url"`
-	Location location `json:"location"`
-	uri      *url.URL
+	URL            string   `json:"url"`
+	Location       location `json:"location"`
+	uri            *url.URL
+	Stats          *stats    `json:"stats"`
+	StatsRetrieved time.Time `json:"statsRetrieved"`
+}
+
+type stats struct {
+	StartTime          time.Time `json:"startTime"`
+	UptimeSeconds      int       `json:"uptimeSeconds"`
+	PendingSessionKeys int       `json:"numPendingSessionKeys"`
+	ActiveSessions     int       `json:"numActiveSessions"`
+	Connections        int       `json:"numConnections"`
+	Proxies            int       `json:"numProxies"`
+	BytesProxied       int       `json:"bytesProxied"`
+	GoVersion          string    `json:"goVersion"`
+	GoOS               string    `json:"goOS"`
+	GoArch             string    `json:"goArch"`
+	GoMaxProcs         int       `json:"goMaxProcs"`
+	GoRoutines         int       `json:"goNumRoutine"`
+	Rates              []int64   `json:"kbps10s1m5m15m30m60m"`
+	Options            struct {
+		NetworkTimeout int      `json:"network-timeout"`
+		PintInterval   int      `json:"ping-interval"`
+		MessageTimeout int      `json:"message-timeout"`
+		SessionRate    int      `json:"per-session-rate"`
+		GlobalRate     int      `json:"global-rate"`
+		Pools          []string `json:"pools"`
+		ProvidedBy     string   `json:"provided-by"`
+	} `json:"options"`
 }

 func (r relay) String() string {
@@ -47,9 +81,9 @@ func (r relay) String() string {
 }

 type request struct {
-	relay  relay
-	uri    *url.URL
-	result chan result
+	relay      *relay
+	result     chan result
+	queueTimer *prometheus.Timer
 }

 type result struct {
@@ -58,23 +92,25 @@ type result struct {
 }

 var (
-	testCert       tls.Certificate
-	listen         = ":80"
-	dir            string
-	evictionTime   = time.Hour
-	debug          bool
-	getLRUSize     = 10 << 10
-	getLimitBurst  = 10
-	getLimitAvg    = 1
-	postLRUSize    = 1 << 10
-	postLimitBurst = 2
-	postLimitAvg   = 1
-	getLimit       time.Duration
-	postLimit      time.Duration
-	permRelaysFile string
-	ipHeader       string
-	geoipPath      string
-	proto          string
+	testCert        tls.Certificate
+	knownRelaysFile = filepath.Join(os.TempDir(), "strelaypoolsrv_known_relays")
+	listen          = ":80"
+	dir             string
+	evictionTime    = time.Hour
+	debug           bool
+	getLRUSize      = 10 << 10
+	getLimitBurst   = 10
+	getLimitAvg     = 2
+	postLRUSize     = 1 << 10
+	postLimitBurst  = 2
+	postLimitAvg    = 2
+	getLimit        time.Duration
+	postLimit       time.Duration
+	permRelaysFile  string
+	ipHeader        string
+	geoipPath       string
+	proto           string
+	statsRefresh    = time.Minute / 2

 	getMut      = sync.NewRWMutex()
 	getLRUCache *lru.Cache
@@ -85,26 +121,31 @@ var (
 	requests = make(chan request, 10)

 	mut             = sync.NewRWMutex()
-	knownRelays     = make([]relay, 0)
-	permanentRelays = make([]relay, 0)
+	knownRelays     = make([]*relay, 0)
+	permanentRelays = make([]*relay, 0)
 	evictionTimers  = make(map[string]*time.Timer)
 )

+const (
+	httpStatusEnhanceYourCalm = 429
+)
+
 func main() {
 	flag.StringVar(&listen, "listen", listen, "Listen address")
 	flag.StringVar(&dir, "keys", dir, "Directory where http-cert.pem and http-key.pem is stored for TLS listening")
 	flag.BoolVar(&debug, "debug", debug, "Enable debug output")
 	flag.DurationVar(&evictionTime, "eviction", evictionTime, "After how long the relay is evicted")
 	flag.IntVar(&getLRUSize, "get-limit-cache", getLRUSize, "Get request limiter cache size")
-	flag.IntVar(&getLimitAvg, "get-limit-avg", 2, "Allowed average get request rate, per 10 s")
+	flag.IntVar(&getLimitAvg, "get-limit-avg", getLimitAvg, "Allowed average get request rate, per 10 s")
 	flag.IntVar(&getLimitBurst, "get-limit-burst", getLimitBurst, "Allowed burst get requests")
 	flag.IntVar(&postLRUSize, "post-limit-cache", postLRUSize, "Post request limiter cache size")
-	flag.IntVar(&postLimitAvg, "post-limit-avg", 2, "Allowed average post request rate, per minute")
+	flag.IntVar(&postLimitAvg, "post-limit-avg", postLimitAvg, "Allowed average post request rate, per minute")
 	flag.IntVar(&postLimitBurst, "post-limit-burst", postLimitBurst, "Allowed burst post requests")
 	flag.StringVar(&permRelaysFile, "perm-relays", "", "Path to list of permanent relays")
 	flag.StringVar(&ipHeader, "ip-header", "", "Name of header which holds clients ip:port. Only meaningful when running behind a reverse proxy.")
 	flag.StringVar(&geoipPath, "geoip", "GeoLite2-City.mmdb", "Path to GeoLite2-City database")
 	flag.StringVar(&proto, "protocol", "tcp", "Protocol used for listening. 'tcp' for IPv4 and IPv6, 'tcp4' for IPv4, 'tcp6' for IPv6")
+	flag.DurationVar(&statsRefresh, "stats-refresh", statsRefresh, "Interval at which to refresh relay stats")

 	flag.Parse()

@@ -118,13 +159,31 @@ func main() {
 	var err error

 	if permRelaysFile != "" {
-		loadPermanentRelays(permRelaysFile)
+		permanentRelays = loadRelays(permRelaysFile)
 	}

 	testCert = createTestCertificate()

 	go requestProcessor()

+	// Load relays from cache in the background.
+	// Load them in a serial fashion to make sure any genuine requests
+	// are not dropped.
+	go func() {
+		for _, relay := range loadRelays(knownRelaysFile) {
+			resultChan := make(chan result)
+			requests <- request{relay, resultChan, nil}
+			result := <-resultChan
+			if result.err != nil {
+				relayTestsTotal.WithLabelValues("failed").Inc()
+			} else {
+				relayTestsTotal.WithLabelValues("success").Inc()
+			}
+		}
+		// Run the the stats refresher once the relays are loaded.
+		statsRefresher(statsRefresh)
+	}()
+
 	if dir != "" {
 		if debug {
 			log.Println("Starting TLS listener on", listen)
@@ -169,6 +228,7 @@ func main() {
 	handler := http.NewServeMux()
 	handler.HandleFunc("/", handleAssets)
 	handler.HandleFunc("/endpoint", handleRequest)
+	handler.HandleFunc("/metrics", handleMetrics)

 	srv := http.Server{
 		Handler:     handler,
@@ -181,7 +241,18 @@ func main() {
 	}
 }

+func handleMetrics(w http.ResponseWriter, r *http.Request) {
+	timer := prometheus.NewTimer(metricsRequestsSeconds)
+	// Acquire the mutex just to make sure we're not caught mid-way stats collection
+	mut.RLock()
+	promhttp.Handler().ServeHTTP(w, r)
+	mut.RUnlock()
+	timer.ObserveDuration()
+}
+
 func handleAssets(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Cache-Control", "no-cache, must-revalidate")
+
 	assets := auto.Assets()
 	path := r.URL.Path[1:]
 	if path == "" {
@@ -194,11 +265,28 @@ func handleAssets(w http.ResponseWriter, r *http.Request) {
 		return
 	}

+	etag := fmt.Sprintf("%d", auto.Generated)
+	modified := time.Unix(auto.Generated, 0).UTC()
+
+	w.Header().Set("Last-Modified", modified.Format(http.TimeFormat))
+	w.Header().Set("Etag", etag)
+
 	mtype := mimeTypeForFile(path)
 	if len(mtype) != 0 {
 		w.Header().Set("Content-Type", mtype)
 	}

+	if t, err := time.Parse(http.TimeFormat, r.Header.Get("If-Modified-Since")); err == nil && modified.Add(time.Second).After(t) {
+		w.WriteHeader(http.StatusNotModified)
+		return
+	}
+
+	if match := r.Header.Get("If-None-Match"); match != "" {
+		if strings.Contains(match, etag) {
+			w.WriteHeader(http.StatusNotModified)
+			return
+		}
+	}
 	if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
 		w.Header().Set("Content-Encoding", "gzip")
 	} else {
@@ -241,6 +329,15 @@ func mimeTypeForFile(file string) string {
 }

 func handleRequest(w http.ResponseWriter, r *http.Request) {
+	timer := prometheus.NewTimer(apiRequestsSeconds.WithLabelValues(r.Method))
+
+	lw := NewLoggingResponseWriter(w)
+
+	defer func() {
+		timer.ObserveDuration()
+		apiRequestsTotal.WithLabelValues(r.Method, strconv.Itoa(lw.statusCode)).Inc()
+	}()
+
 	if ipHeader != "" {
 		r.RemoteAddr = r.Header.Get(ipHeader)
 	}
@@ -248,13 +345,13 @@ func handleRequest(w http.ResponseWriter, r *http.Request) {
 	switch r.Method {
 	case "GET":
 		if limit(r.RemoteAddr, getLRUCache, getMut, getLimit, getLimitBurst) {
-			w.WriteHeader(429)
+			w.WriteHeader(httpStatusEnhanceYourCalm)
 			return
 		}
 		handleGetRequest(w, r)
 	case "POST":
 		if limit(r.RemoteAddr, postLRUCache, postMut, postLimit, postLimitBurst) {
-			w.WriteHeader(429)
+			w.WriteHeader(httpStatusEnhanceYourCalm)
 			return
 		}
 		handlePostRequest(w, r)
@@ -278,7 +375,7 @@ func handleGetRequest(w http.ResponseWriter, r *http.Request) {
 		relays[i], relays[j] = relays[j], relays[i]
 	}

-	json.NewEncoder(w).Encode(map[string][]relay{
+	json.NewEncoder(w).Encode(map[string][]*relay{
 		"relays": relays,
 	})
 }
@@ -315,13 +412,9 @@ func handlePostRequest(w http.ResponseWriter, r *http.Request) {
 	}

 	// Get the IP address of the client
-	rhost, _, err := net.SplitHostPort(r.RemoteAddr)
-	if err != nil {
-		if debug {
-			log.Println("Failed to split remote address", r.RemoteAddr)
-		}
-		http.Error(w, err.Error(), 500)
-		return
+	rhost := r.RemoteAddr
+	if host, _, err := net.SplitHostPort(rhost); err == nil {
+		rhost = host
 	}

 	ip := net.ParseIP(host)
@@ -333,18 +426,18 @@ func handlePostRequest(w http.ResponseWriter, r *http.Request) {
 		if debug {
 			log.Println("IP address advertised does not match client IP address", r.RemoteAddr, uri)
 		}
-		http.Error(w, "IP address does not match client IP", http.StatusUnauthorized)
+		http.Error(w, fmt.Sprintf("IP advertised %s does not match client IP %s", host, rhost), http.StatusUnauthorized)
 		return
 	}
+
 	newRelay.uri = uri
-	newRelay.Location = getLocation(uri.Host)

 	for _, current := range permanentRelays {
 		if current.uri.Host == newRelay.uri.Host {
 			if debug {
 				log.Println("Asked to add a relay", newRelay, "which exists in permanent list")
 			}
-			http.Error(w, "Invalid request", 500)
+			http.Error(w, "Invalid request", http.StatusBadRequest)
 			return
 		}
 	}
@@ -352,78 +445,105 @@ func handlePostRequest(w http.ResponseWriter, r *http.Request) {
 	reschan := make(chan result)

 	select {
-	case requests <- request{newRelay, uri, reschan}:
+	case requests <- request{&newRelay, reschan, prometheus.NewTimer(relayTestActionsSeconds.WithLabelValues("queue"))}:
 		result := <-reschan
 		if result.err != nil {
-			http.Error(w, result.err.Error(), 500)
+			relayTestsTotal.WithLabelValues("failed").Inc()
+			http.Error(w, result.err.Error(), http.StatusBadRequest)
 			return
 		}
+		relayTestsTotal.WithLabelValues("success").Inc()
 		w.Header().Set("Content-Type", "application/json; charset=utf-8")
 		json.NewEncoder(w).Encode(map[string]time.Duration{
 			"evictionIn": result.eviction,
 		})

 	default:
+		relayTestsTotal.WithLabelValues("dropped").Inc()
 		if debug {
 			log.Println("Dropping request")
 		}
-		w.WriteHeader(429)
+		w.WriteHeader(httpStatusEnhanceYourCalm)
 	}
 }

 func requestProcessor() {
 	for request := range requests {
-		if debug {
-			log.Println("Request for", request.relay)
-		}
-		if !client.TestRelay(request.uri, []tls.Certificate{testCert}, time.Second, 2*time.Second, 3) {
-			if debug {
-				log.Println("Test for relay", request.relay, "failed")
-			}
-			request.result <- result{fmt.Errorf("test failed"), 0}
-			continue
+		if request.queueTimer != nil {
+			request.queueTimer.ObserveDuration()
 		}

-		mut.Lock()
-		timer, ok := evictionTimers[request.relay.uri.Host]
-		if ok {
-			if debug {
-				log.Println("Stopping existing timer for", request.relay)
-			}
-			timer.Stop()
-		}
-
-		for i, current := range knownRelays {
-			if current.uri.Host == request.relay.uri.Host {
-				if debug {
-					log.Println("Relay", request.relay, "already exists")
-				}
-
-				// Evict the old entry anyway, as configuration might have changed.
-				last := len(knownRelays) - 1
-				knownRelays[i] = knownRelays[last]
-				knownRelays = knownRelays[:last]
-
-				goto found
-			}
-		}
-
-		if debug {
-			log.Println("Adding new relay", request.relay)
-		}
-
-	found:
-
-		knownRelays = append(knownRelays, request.relay)
-
-		evictionTimers[request.relay.uri.Host] = time.AfterFunc(evictionTime, evict(request.relay))
-		mut.Unlock()
-		request.result <- result{nil, evictionTime}
+		timer := prometheus.NewTimer(relayTestActionsSeconds.WithLabelValues("test"))
+		handleRelayTest(request)
+		timer.ObserveDuration()
 	}
-
 }

-func evict(relay relay) func() {
+func handleRelayTest(request request) {
+	if debug {
+		log.Println("Request for", request.relay)
+	}
+	if !client.TestRelay(request.relay.uri, []tls.Certificate{testCert}, time.Second, 2*time.Second, 3) {
+		if debug {
+			log.Println("Test for relay", request.relay, "failed")
+		}
+		request.result <- result{fmt.Errorf("connection test failed"), 0}
+		return
+	}
+
+	stats := fetchStats(request.relay)
+	location := getLocation(request.relay.uri.Host)
+
+	mut.Lock()
+	if stats != nil {
+		updateMetrics(request.relay.uri.Host, *stats, location)
+	}
+	request.relay.Stats = stats
+	request.relay.StatsRetrieved = time.Now()
+	request.relay.Location = location
+
+	timer, ok := evictionTimers[request.relay.uri.Host]
+	if ok {
+		if debug {
+			log.Println("Stopping existing timer for", request.relay)
+		}
+		timer.Stop()
+	}
+
+	for i, current := range knownRelays {
+		if current.uri.Host == request.relay.uri.Host {
+			if debug {
+				log.Println("Relay", request.relay, "already exists")
+			}
+
+			// Evict the old entry anyway, as configuration might have changed.
+			last := len(knownRelays) - 1
+			knownRelays[i] = knownRelays[last]
+			knownRelays = knownRelays[:last]
+
+			goto found
+		}
+	}
+
+	if debug {
+		log.Println("Adding new relay", request.relay)
+	}
+
+found:
+
+	knownRelays = append(knownRelays, request.relay)
+	evictionTimers[request.relay.uri.Host] = time.AfterFunc(evictionTime, evict(request.relay))
+
+	mut.Unlock()
+
+	if err := saveRelays(knownRelaysFile, knownRelays); err != nil {
+		log.Println("Failed to write known relays: " + err.Error())
+	}
+
+	request.result <- result{nil, evictionTime}
+}
+
+func evict(relay *relay) func() {
 	return func() {
 		mut.Lock()
 		defer mut.Unlock()
@@ -438,6 +558,7 @@ func evict(relay relay) func() {
 				last := len(knownRelays) - 1
 				knownRelays[i] = knownRelays[last]
 				knownRelays = knownRelays[:last]
+				deleteMetrics(current.uri.Host)
 			}
 		}
 		delete(evictionTimers, relay.uri.Host)
@@ -445,13 +566,12 @@ func evict(relay relay) func() {
 }

 func limit(addr string, cache *lru.Cache, lock sync.RWMutex, intv time.Duration, burst int) bool {
-	host, _, err := net.SplitHostPort(addr)
-	if err != nil {
-		return false
+	if host, _, err := net.SplitHostPort(addr); err == nil {
+		addr = host
 	}

 	lock.RLock()
-	bkt, ok := cache.Get(host)
+	bkt, ok := cache.Get(addr)
 	lock.RUnlock()
 	if ok {
 		bkt := bkt.(*rate.Limiter)
@@ -461,18 +581,20 @@ func limit(addr string, cache *lru.Cache, lock sync.RWMutex, intv time.Duration,
 		}
 	} else {
 		lock.Lock()
-		cache.Add(host, rate.NewLimiter(rate.Every(intv), burst))
+		cache.Add(addr, rate.NewLimiter(rate.Every(intv), burst))
 		lock.Unlock()
 	}
 	return false
 }

-func loadPermanentRelays(file string) {
+func loadRelays(file string) []*relay {
 	content, err := ioutil.ReadFile(file)
 	if err != nil {
-		log.Fatal(err)
+		log.Println("Failed to load relays: " + err.Error())
+		return nil
 	}

+	var relays []*relay
 	for _, line := range strings.Split(string(content), "\n") {
 		if len(line) == 0 {
 			continue
@@ -481,21 +603,30 @@ func loadPermanentRelays(file string) {
 		uri, err := url.Parse(line)
 		if err != nil {
 			if debug {
-				log.Println("Skipping permanent relay", line, "due to parse error", err)
+				log.Println("Skipping relay", line, "due to parse error", err)
 			}
 			continue

 		}

-		permanentRelays = append(permanentRelays, relay{
+		relays = append(relays, &relay{
 			URL:      line,
 			Location: getLocation(uri.Host),
 			uri:      uri,
 		})
 		if debug {
-			log.Println("Adding permanent relay", line)
+			log.Println("Adding relay", line)
 		}
 	}
+	return relays
+}
+
+func saveRelays(file string, relays []*relay) error {
+	var content string
+	for _, relay := range relays {
+		content += relay.uri.String() + "\n"
+	}
+	return ioutil.WriteFile(file, []byte(content), 0777)
 }

 func createTestCertificate() tls.Certificate {
@@ -505,7 +636,7 @@ func createTestCertificate() tls.Certificate {
 	}

 	certFile, keyFile := filepath.Join(tmpDir, "cert.pem"), filepath.Join(tmpDir, "key.pem")
-	cert, err := tlsutil.NewCertificate(certFile, keyFile, "relaypoolsrv", 3072)
+	cert, err := tlsutil.NewCertificate(certFile, keyFile, "relaypoolsrv")
 	if err != nil {
 		log.Fatalln("Failed to create test X509 key pair:", err)
 	}
@@ -514,6 +645,8 @@ func createTestCertificate() tls.Certificate {
 }

 func getLocation(host string) location {
+	timer := prometheus.NewTimer(locationLookupSeconds)
+	defer timer.ObserveDuration()
 	db, err := geoip2.Open(geoipPath)
 	if err != nil {
 		return location{}
@@ -531,7 +664,24 @@ func getLocation(host string) location {
 	}

 	return location{
-		Latitude:  city.Location.Latitude,
 		Longitude: city.Location.Longitude,
+		Latitude:  city.Location.Latitude,
+		City:      city.City.Names["en"],
+		Country:   city.Country.IsoCode,
+		Continent: city.Continent.Code,
 	}
 }
+
+type loggingResponseWriter struct {
+	http.ResponseWriter
+	statusCode int
+}
+
+func NewLoggingResponseWriter(w http.ResponseWriter) *loggingResponseWriter {
+	return &loggingResponseWriter{w, http.StatusOK}
+}
+
+func (lrw *loggingResponseWriter) WriteHeader(code int) {
+	lrw.statusCode = code
+	lrw.ResponseWriter.WriteHeader(code)
+}
--- a/cmd/strelaypoolsrv/stats.go
+++ b/cmd/strelaypoolsrv/stats.go
@@ -0,0 +1,259 @@
+// Copyright (C) 2018 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
+
+package main
+
+import (
+	"encoding/json"
+	"net"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/syncthing/syncthing/lib/sync"
+)
+
+func init() {
+	processCollectorOpts := prometheus.ProcessCollectorOpts{
+		Namespace: "syncthing_relaypoolsrv",
+		PidFn: func() (int, error) {
+			return os.Getpid(), nil
+		},
+	}
+
+	prometheus.MustRegister(
+		prometheus.NewProcessCollector(processCollectorOpts),
+	)
+}
+
+var (
+	statusClient = http.Client{
+		Timeout: 5 * time.Second,
+	}
+
+	apiRequestsTotal   = makeCounter("api_requests_total", "Number of API requests.", "type", "result")
+	apiRequestsSeconds = makeSummary("api_requests_seconds", "Latency of API requests.", "type")
+
+	relayTestsTotal         = makeCounter("tests_total", "Number of relay tests.", "result")
+	relayTestActionsSeconds = makeSummary("test_actions_seconds", "Latency of relay test actions.", "type")
+
+	locationLookupSeconds = makeSummary("location_lookup_seconds", "Latency of location lookups.").WithLabelValues()
+
+	metricsRequestsSeconds = makeSummary("metrics_requests_seconds", "Latency of metric requests.").WithLabelValues()
+	scrapeSeconds          = makeSummary("relay_scrape_seconds", "Latency of metric scrapes from remote relays.", "result")
+
+	relayUptime             = makeGauge("relay_uptime", "Uptime of relay", "relay")
+	relayPendingSessionKeys = makeGauge("relay_pending_session_keys", "Number of pending session keys (two keys per session, one per each side of the connection)", "relay")
+	relayActiveSessions     = makeGauge("relay_active_sessions", "Number of sessions that are happening, a session contains two parties", "relay")
+	relayConnections        = makeGauge("relay_connections", "Number of devices connected to the relay", "relay")
+	relayProxies            = makeGauge("relay_proxies", "Number of active proxy routines sending data between peers (two proxies per session, one for each way)", "relay")
+	relayBytesProxied       = makeGauge("relay_bytes_proxied", "Number of bytes proxied by the relay", "relay")
+	relayGoRoutines         = makeGauge("relay_go_routines", "Number of Go routines in the process", "relay")
+	relaySessionRate        = makeGauge("relay_session_rate", "Rate applied per session", "relay")
+	relayGlobalRate         = makeGauge("relay_global_rate", "Global rate applied on the whole relay", "relay")
+	relayBuildInfo          = makeGauge("relay_build_info", "Build information about a relay", "relay", "go_version", "go_os", "go_arch")
+	relayLocationInfo       = makeGauge("relay_location_info", "Location information about a relay", "relay", "city", "country", "continent")
+
+	lastStats = make(map[string]stats)
+)
+
+func makeGauge(name string, help string, labels ...string) *prometheus.GaugeVec {
+	gauge := prometheus.NewGaugeVec(
+		prometheus.GaugeOpts{
+			Namespace: "syncthing",
+			Subsystem: "relaypoolsrv",
+			Name:      name,
+			Help:      help,
+		},
+		labels,
+	)
+	prometheus.MustRegister(gauge)
+	return gauge
+}
+
+func makeSummary(name string, help string, labels ...string) *prometheus.SummaryVec {
+	summary := prometheus.NewSummaryVec(
+		prometheus.SummaryOpts{
+			Namespace:  "syncthing",
+			Subsystem:  "relaypoolsrv",
+			Name:       name,
+			Help:       help,
+			Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+		},
+		labels,
+	)
+	prometheus.MustRegister(summary)
+	return summary
+}
+
+func makeCounter(name string, help string, labels ...string) *prometheus.CounterVec {
+	counter := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace: "syncthing",
+			Subsystem: "relaypoolsrv",
+			Name:      name,
+			Help:      help,
+		},
+		labels,
+	)
+	prometheus.MustRegister(counter)
+	return counter
+}
+
+func statsRefresher(interval time.Duration) {
+	ticker := time.NewTicker(interval)
+	for range ticker.C {
+		refreshStats()
+	}
+}
+
+type statsFetchResult struct {
+	relay *relay
+	stats *stats
+}
+
+func refreshStats() {
+	mut.RLock()
+	relays := append(permanentRelays, knownRelays...)
+	mut.RUnlock()
+
+	now := time.Now()
+	wg := sync.NewWaitGroup()
+
+	results := make(chan statsFetchResult, len(relays))
+	for _, rel := range relays {
+		wg.Add(1)
+		go func(rel *relay) {
+			t0 := time.Now()
+			stats := fetchStats(rel)
+			duration := time.Since(t0).Seconds()
+			result := "success"
+			if stats == nil {
+				result = "failed"
+			}
+			scrapeSeconds.WithLabelValues(result).Observe(duration)
+
+			results <- statsFetchResult{
+				relay: rel,
+				stats: fetchStats(rel),
+			}
+			wg.Done()
+		}(rel)
+	}
+
+	wg.Wait()
+	close(results)
+
+	mut.Lock()
+	relayBuildInfo.Reset()
+	relayLocationInfo.Reset()
+	for result := range results {
+		result.relay.StatsRetrieved = now
+		result.relay.Stats = result.stats
+		if result.stats == nil {
+			deleteMetrics(result.relay.uri.Host)
+		} else {
+			updateMetrics(result.relay.uri.Host, *result.stats, result.relay.Location)
+		}
+	}
+	mut.Unlock()
+}
+
+func fetchStats(relay *relay) *stats {
+	statusAddr := relay.uri.Query().Get("statusAddr")
+	if statusAddr == "" {
+		statusAddr = ":22070"
+	}
+
+	statusHost, statusPort, err := net.SplitHostPort(statusAddr)
+	if err != nil {
+		return nil
+	}
+
+	if statusHost == "" {
+		if host, _, err := net.SplitHostPort(relay.uri.Host); err != nil {
+			return nil
+		} else {
+			statusHost = host
+		}
+	}
+
+	url := "http://" + net.JoinHostPort(statusHost, statusPort) + "/status"
+
+	response, err := statusClient.Get(url)
+	if err != nil {
+		return nil
+	}
+
+	var stats stats
+
+	if json.NewDecoder(response.Body).Decode(&stats); err != nil {
+		return nil
+	}
+	return &stats
+}
+
+func updateMetrics(host string, stats stats, location location) {
+	if stats.GoVersion != "" || stats.GoOS != "" || stats.GoArch != "" {
+		relayBuildInfo.WithLabelValues(host, stats.GoVersion, stats.GoOS, stats.GoArch).Add(1)
+	}
+	if location.City != "" || location.Country != "" || location.Continent != "" {
+		relayLocationInfo.WithLabelValues(host, location.City, location.Country, location.Continent).Add(1)
+	}
+
+	if lastStat, ok := lastStats[host]; ok {
+		stats = mergeStats(stats, lastStat)
+	}
+
+	relayUptime.WithLabelValues(host).Set(float64(stats.UptimeSeconds))
+	relayPendingSessionKeys.WithLabelValues(host).Set(float64(stats.PendingSessionKeys))
+	relayActiveSessions.WithLabelValues(host).Set(float64(stats.ActiveSessions))
+	relayConnections.WithLabelValues(host).Set(float64(stats.Connections))
+	relayProxies.WithLabelValues(host).Set(float64(stats.Proxies))
+	relayBytesProxied.WithLabelValues(host).Set(float64(stats.BytesProxied))
+	relayGoRoutines.WithLabelValues(host).Set(float64(stats.GoRoutines))
+	relaySessionRate.WithLabelValues(host).Set(float64(stats.Options.SessionRate))
+	relayGlobalRate.WithLabelValues(host).Set(float64(stats.Options.GlobalRate))
+	lastStats[host] = stats
+}
+
+func deleteMetrics(host string) {
+	relayUptime.DeleteLabelValues(host)
+	relayPendingSessionKeys.DeleteLabelValues(host)
+	relayActiveSessions.DeleteLabelValues(host)
+	relayConnections.DeleteLabelValues(host)
+	relayProxies.DeleteLabelValues(host)
+	relayBytesProxied.DeleteLabelValues(host)
+	relayGoRoutines.DeleteLabelValues(host)
+	relaySessionRate.DeleteLabelValues(host)
+	relayGlobalRate.DeleteLabelValues(host)
+	delete(lastStats, host)
+}
+
+// Due to some unexplainable behaviour, some of the numbers sometimes travel slightly backwards (by less than 1%)
+// This happens between scrapes, which is 30s, so this can't be a race.
+// This causes prometheus to assume a "rate reset", hence causes phenomenal spikes.
+// One of the number that moves backwards is BytesProxied, which atomically increments a counter with numeric value
+// returned by net.Conn.Read(). I don't think that can return a negative value, so I have no idea what's going on.
+func mergeStats(new stats, old stats) stats {
+	new.UptimeSeconds = mergeValue(new.UptimeSeconds, old.UptimeSeconds)
+	new.PendingSessionKeys = mergeValue(new.PendingSessionKeys, old.PendingSessionKeys)
+	new.ActiveSessions = mergeValue(new.ActiveSessions, old.ActiveSessions)
+	new.Connections = mergeValue(new.Connections, old.Connections)
+	new.Proxies = mergeValue(new.Proxies, old.Proxies)
+	new.BytesProxied = mergeValue(new.BytesProxied, old.BytesProxied)
+	new.GoRoutines = mergeValue(new.GoRoutines, old.GoRoutines)
+	new.Options.SessionRate = mergeValue(new.Options.SessionRate, old.Options.SessionRate)
+	new.Options.GlobalRate = mergeValue(new.Options.GlobalRate, old.Options.GlobalRate)
+	return new
+}
+
+func mergeValue(new, old int) int {
+	if new >= old {
+		return new // normal increase
+	}
+	if float64(new) > 0.99*float64(old) {
+		return old // slight backward movement
+	}
+	return new // reset (relay restart)
+}
--- a/cmd/strelaypoolsrv/stats_test.go
+++ b/cmd/strelaypoolsrv/stats_test.go
@@ -0,0 +1,21 @@
+// Copyright (C) 2015 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
+
+package main
+
+import (
+	"testing"
+)
+
+func TestMerge(t *testing.T) {
+	if mergeValue(1001, 1000) != 1001 {
+		t.Error("the computer says no")
+	}
+
+	if mergeValue(999, 1000) != 1000 {
+		t.Error("the computer says no")
+	}
+
+	if mergeValue(1, 1000) != 1 {
+		t.Error("the computer says no")
+	}
+}
--- a/cmd/strelaysrv/listener.go
+++ b/cmd/strelaysrv/listener.go
@@ -104,7 +104,9 @@ func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
 	go messageReader(conn, messages, errors)

 	pingTicker := time.NewTicker(pingInterval)
+	defer pingTicker.Stop()
 	timeoutTicker := time.NewTimer(networkTimeout)
+	defer timeoutTicker.Stop()
 	joined := false

 	for {
--- a/cmd/strelaysrv/main.go
+++ b/cmd/strelaysrv/main.go
@@ -64,12 +64,13 @@ var (

 	limitCheckTimer *time.Timer

-	sessionLimitBps int
-	globalLimitBps  int
-	overLimit       int32
-	descriptorLimit int64
-	sessionLimiter  *rate.Limiter
-	globalLimiter   *rate.Limiter
+	sessionLimitBps   int
+	globalLimitBps    int
+	overLimit         int32
+	descriptorLimit   int64
+	sessionLimiter    *rate.Limiter
+	globalLimiter     *rate.Limiter
+	networkBufferSize int

 	statusAddr       string
 	poolAddrs        string
@@ -81,8 +82,16 @@ var (
 	natLease   int
 	natRenewal int
 	natTimeout int
+
+	pprofEnabled bool
 )

+// httpClient is the HTTP client we use for outbound requests. It has a
+// timeout and may get further options set during initialization.
+var httpClient = &http.Client{
+	Timeout: 30 * time.Second,
+}
+
 func main() {
 	log.SetFlags(log.Lshortfile | log.LstdFlags)

@@ -105,6 +114,8 @@ func main() {
 	flag.IntVar(&natLease, "nat-lease", 60, "NAT lease length in minutes")
 	flag.IntVar(&natRenewal, "nat-renewal", 30, "NAT renewal frequency in minutes")
 	flag.IntVar(&natTimeout, "nat-timeout", 10, "NAT discovery timeout in seconds")
+	flag.BoolVar(&pprofEnabled, "pprof", false, "Enable the built in profiling on the status server")
+	flag.IntVar(&networkBufferSize, "network-buffer", 2048, "Network buffer size (two of these per proxied connection)")
 	flag.Parse()

 	if extAddress == "" {
@@ -124,14 +135,14 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
+
 	if laddr.IP != nil && !laddr.IP.IsUnspecified() {
+		// We bind to a specific address. Our outgoing HTTP requests should
+		// also come from that address.
 		laddr.Port = 0
-		transport, ok := http.DefaultTransport.(*http.Transport)
-		if ok {
-			transport.Dial = (&net.Dialer{
-				Timeout:   30 * time.Second,
-				LocalAddr: laddr,
-			}).Dial
+		boundDialer := &net.Dialer{LocalAddr: laddr}
+		httpClient.Transport = &http.Transport{
+			DialContext: boundDialer.DialContext,
 		}
 	}

@@ -155,7 +166,7 @@ func main() {
 	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
 	if err != nil {
 		log.Println("Failed to load keypair. Generating one, this might take a while...")
-		cert, err = tlsutil.NewCertificate(certFile, keyFile, "strelaysrv", 3072)
+		cert, err = tlsutil.NewCertificate(certFile, keyFile, "strelaysrv")
 		if err != nil {
 			log.Fatalln("Failed to generate X509 key pair:", err)
 		}
--- a/cmd/strelaysrv/pool.go
+++ b/cmd/strelaysrv/pool.go
@@ -7,7 +7,6 @@ import (
 	"encoding/json"
 	"io/ioutil"
 	"log"
-	"net/http"
 	"net/url"
 	"time"
 )
@@ -27,7 +26,7 @@ func poolHandler(pool string, uri *url.URL, mapping mapping) {
 			uriCopy.String(),
 		})

-		resp, err := http.Post(pool, "application/json", &b)
+		resp, err := httpClient.Post(pool, "application/json", &b)
 		if err != nil {
 			log.Println("Error joining pool", pool, err)
 		} else if resp.StatusCode == 500 {
--- a/cmd/strelaysrv/session.go
+++ b/cmd/strelaysrv/session.go
@@ -22,7 +22,7 @@ import (
 var (
 	sessionMut      = sync.RWMutex{}
 	activeSessions  = make([]*session, 0)
-	pendingSessions = make(map[string]*session, 0)
+	pendingSessions = make(map[string]*session)
 	numProxies      int64
 	bytesProxied    int64
 )
@@ -189,7 +189,7 @@ done:
 	// We can end up here in 3 cases:
 	// 1. Timeout joining, in which case there are potentially entries in pendingSessions
 	// 2. General session end/timeout, in which case there are entries in activeSessions
-	// 3. Protocol handler calls dropSession as one of it's clients disconnects.
+	// 3. Protocol handler calls dropSession as one of its clients disconnects.

 	sessionMut.Lock()
 	delete(pendingSessions, string(s.serverkey))
@@ -254,7 +254,7 @@ func (s *session) proxy(c1, c2 net.Conn) error {
 	atomic.AddInt64(&numProxies, 1)
 	defer atomic.AddInt64(&numProxies, -1)

-	buf := make([]byte, 65536)
+	buf := make([]byte, networkBufferSize)
 	for {
 		c1.SetReadDeadline(time.Now().Add(networkTimeout))
 		n, err := c1.Read(buf)
--- a/cmd/strelaysrv/status.go
+++ b/cmd/strelaysrv/status.go
@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"log"
 	"net/http"
+	"net/http/pprof"
 	"runtime"
 	"sync/atomic"
 	"time"
@@ -18,6 +19,9 @@ func statusService(addr string) {

 	handler := http.NewServeMux()
 	handler.HandleFunc("/status", getStatus)
+	if pprofEnabled {
+		handler.HandleFunc("/debug/pprof/", pprof.Index)
+	}

 	srv := http.Server{
 		Addr:        addr,
@@ -36,6 +40,10 @@ func getStatus(w http.ResponseWriter, r *http.Request) {

 	sessionMut.Lock()
 	// This can potentially be double the number of pending sessions, as each session has two keys, one for each side.
+	status["version"] = Version
+	status["buildHost"] = BuildHost
+	status["buildUser"] = BuildUser
+	status["buildDate"] = BuildDate
 	status["startTime"] = rc.startTime
 	status["uptimeSeconds"] = time.Since(rc.startTime) / time.Second
 	status["numPendingSessionKeys"] = len(pendingSessions)
--- a/cmd/stsigtool/main.go
+++ b/cmd/stsigtool/main.go
@@ -24,7 +24,7 @@ func main() {
 	flag.Parse()

 	if flag.NArg() < 1 {
-		log.Println(`Usage:
+		log.Print(`Usage:
 	stsigtool <command>

 Where command is one of:
@@ -40,6 +40,7 @@ Where command is one of:

 	verify <signaturefile> <datafile> <pubkeyfile>
 		- verify a signature, using the specified public key file
+
 `)
 	}

--- a/cmd/syncthing/auditservice_test.go
+++ b/cmd/syncthing/auditservice_test.go
@@ -37,7 +37,7 @@ func TestAuditService(t *testing.T) {
 	// This event should not be logged, since we have stopped.
 	events.Default.Log(events.ConfigSaved, "the third event")

-	result := string(buf.Bytes())
+	result := buf.String()
 	t.Log(result)

 	if strings.Contains(result, "first event") {
--- a/cmd/syncthing/gui.go
+++ b/cmd/syncthing/gui.go
@@ -7,15 +7,19 @@
 package main

 import (
+	"bytes"
 	"crypto/tls"
 	"encoding/json"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net"
 	"net/http"
+	"net/url"
 	"os"
 	"path/filepath"
 	"reflect"
+	"regexp"
 	"runtime"
 	"runtime/pprof"
 	"sort"
@@ -23,26 +27,33 @@ import (
 	"strings"
 	"time"

-	"github.com/rcrowley/go-metrics"
+	metrics "github.com/rcrowley/go-metrics"
+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/connections"
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/discover"
 	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/fs"
+	"github.com/syncthing/syncthing/lib/locations"
 	"github.com/syncthing/syncthing/lib/logger"
 	"github.com/syncthing/syncthing/lib/model"
-	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/rand"
 	"github.com/syncthing/syncthing/lib/stats"
 	"github.com/syncthing/syncthing/lib/sync"
 	"github.com/syncthing/syncthing/lib/tlsutil"
 	"github.com/syncthing/syncthing/lib/upgrade"
+	"github.com/syncthing/syncthing/lib/versioner"
 	"github.com/vitrun/qart/qr"
 	"golang.org/x/crypto/bcrypt"
 )

 var (
 	startTime = time.Now()
+
+	// matches a bcrypt hash and not too much else
+	bcryptExpr = regexp.MustCompile(`^\$2[aby]\$\d+\$.{50,}`)
 )

 const (
@@ -78,7 +89,10 @@ type modelIntf interface {
 	GlobalDirectoryTree(folder, prefix string, levels int, dirsonly bool) map[string]interface{}
 	Completion(device protocol.DeviceID, folder string) model.FolderCompletion
 	Override(folder string)
-	NeedFolderFiles(folder string, page, perpage int) ([]db.FileInfoTruncated, []db.FileInfoTruncated, []db.FileInfoTruncated, int)
+	Revert(folder string)
+	NeedFolderFiles(folder string, page, perpage int) ([]db.FileInfoTruncated, []db.FileInfoTruncated, []db.FileInfoTruncated)
+	RemoteNeedFolderFiles(device protocol.DeviceID, folder string, page, perpage int) ([]db.FileInfoTruncated, error)
+	LocalChangedFiles(folder string, page, perpage int) []db.FileInfoTruncated
 	NeedSize(folder string) db.Counts
 	ConnectionStats() map[string]interface{}
 	DeviceStatistics() map[string]stats.DeviceStatistics
@@ -86,32 +100,39 @@ type modelIntf interface {
 	CurrentFolderFile(folder string, file string) (protocol.FileInfo, bool)
 	CurrentGlobalFile(folder string, file string) (protocol.FileInfo, bool)
 	ResetFolder(folder string)
-	Availability(folder, file string, version protocol.Vector, block protocol.BlockInfo) []model.Availability
+	Availability(folder string, file protocol.FileInfo, block protocol.BlockInfo) []model.Availability
 	GetIgnores(folder string) ([]string, []string, error)
+	GetFolderVersions(folder string) (map[string][]versioner.FileVersion, error)
+	RestoreFolderVersions(folder string, versions map[string]time.Time) (map[string]string, error)
 	SetIgnores(folder string, content []string) error
 	DelayScan(folder string, next time.Duration)
 	ScanFolder(folder string) error
 	ScanFolders() map[string]error
 	ScanFolderSubdirs(folder string, subs []string) error
 	BringToFront(folder, file string)
-	ConnectedTo(deviceID protocol.DeviceID) bool
+	Connection(deviceID protocol.DeviceID) (connections.Connection, bool)
 	GlobalSize(folder string) db.Counts
 	LocalSize(folder string) db.Counts
+	ReceiveOnlyChangedSize(folder string) db.Counts
 	CurrentSequence(folder string) (int64, bool)
 	RemoteSequence(folder string) (int64, bool)
 	State(folder string) (string, time.Time, error)
+	UsageReportingStats(version int, preview bool) map[string]interface{}
+	FolderErrors(folder string) ([]model.FileError, error)
+	WatchError(folder string) error
 }

 type configIntf interface {
 	GUI() config.GUIConfiguration
+	LDAP() config.LDAPConfiguration
 	RawCopy() config.Configuration
 	Options() config.OptionsConfiguration
-	Replace(cfg config.Configuration) error
+	Replace(cfg config.Configuration) (config.Waiter, error)
 	Subscribe(c config.Committer)
 	Folders() map[string]config.FolderConfiguration
 	Devices() map[protocol.DeviceID]config.DeviceConfiguration
-	SetDevice(config.DeviceConfiguration) error
-	SetDevices([]config.DeviceConfiguration) error
+	SetDevice(config.DeviceConfiguration) (config.Waiter, error)
+	SetDevices([]config.DeviceConfiguration) (config.Waiter, error)
 	Save() error
 	ListenAddresses() []string
 	RequiresRestart() bool
@@ -119,6 +140,7 @@ type configIntf interface {

 type connectionsIntf interface {
 	Status() map[string]interface{}
+	NATType() string
 }

 type rater interface {
@@ -166,30 +188,21 @@ func (s *apiService) getListener(guiCfg config.GUIConfiguration) (net.Listener,
 			name = tlsDefaultCommonName
 		}

-		cert, err = tlsutil.NewCertificate(s.httpsCertFile, s.httpsKeyFile, name, httpsRSABits)
+		cert, err = tlsutil.NewCertificate(s.httpsCertFile, s.httpsKeyFile, name)
 	}
 	if err != nil {
 		return nil, err
 	}
-	tlsCfg := &tls.Config{
-		Certificates: []tls.Certificate{cert},
-		MinVersion:   tls.VersionTLS10, // No SSLv3
-		CipherSuites: []uint16{
-			// No RC4
-			tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
-			tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
-			tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
-			tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
-			tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
-			tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
-			tls.TLS_RSA_WITH_AES_128_CBC_SHA,
-			tls.TLS_RSA_WITH_AES_256_CBC_SHA,
-			tls.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
-			tls.TLS_RSA_WITH_3DES_EDE_CBC_SHA,
-		},
-	}
+	tlsCfg := tlsutil.SecureDefault()
+	tlsCfg.Certificates = []tls.Certificate{cert}

-	rawListener, err := net.Listen("tcp", guiCfg.Address())
+	if guiCfg.Network() == "unix" {
+		// When listening on a UNIX socket we should unlink before bind,
+		// lest we get a "bind: address already in use". We don't
+		// particularly care if this succeeds or not.
+		os.Remove(guiCfg.Address())
+	}
+	rawListener, err := net.Listen(guiCfg.Network(), guiCfg.Address())
 	if err != nil {
 		return nil, err
 	}
@@ -205,14 +218,14 @@ func sendJSON(w http.ResponseWriter, jsonObject interface{}) {
 	w.Header().Set("Content-Type", "application/json; charset=utf-8")
 	// Marshalling might fail, in which case we should return a 500 with the
 	// actual error.
-	bs, err := json.Marshal(jsonObject)
+	bs, err := json.MarshalIndent(jsonObject, "", "  ")
 	if err != nil {
 		// This Marshal() can't fail though.
 		bs, _ = json.Marshal(map[string]string{"error": err.Error()})
 		http.Error(w, string(bs), http.StatusInternalServerError)
 		return
 	}
-	w.Write(bs)
+	fmt.Fprintf(w, "%s\n", bs)
 }

 func (s *apiService) Serve() {
@@ -247,8 +260,13 @@ func (s *apiService) Serve() {
 	getRestMux.HandleFunc("/rest/db/file", s.getDBFile)                          // folder file
 	getRestMux.HandleFunc("/rest/db/ignores", s.getDBIgnores)                    // folder
 	getRestMux.HandleFunc("/rest/db/need", s.getDBNeed)                          // folder [perpage] [page]
+	getRestMux.HandleFunc("/rest/db/remoteneed", s.getDBRemoteNeed)              // device folder [perpage] [page]
+	getRestMux.HandleFunc("/rest/db/localchanged", s.getDBLocalChanged)          // folder
 	getRestMux.HandleFunc("/rest/db/status", s.getDBStatus)                      // folder
 	getRestMux.HandleFunc("/rest/db/browse", s.getDBBrowse)                      // folder [prefix] [dirsonly] [levels]
+	getRestMux.HandleFunc("/rest/folder/versions", s.getFolderVersions)          // folder
+	getRestMux.HandleFunc("/rest/folder/errors", s.getFolderErrors)              // folder
+	getRestMux.HandleFunc("/rest/folder/pullerrors", s.getFolderErrors)          // folder (deprecated)
 	getRestMux.HandleFunc("/rest/events", s.getIndexEvents)                      // [since] [limit] [timeout] [events]
 	getRestMux.HandleFunc("/rest/events/disk", s.getDiskEvents)                  // [since] [limit] [timeout]
 	getRestMux.HandleFunc("/rest/stats/device", s.getDeviceStats)                // -
@@ -276,7 +294,9 @@ func (s *apiService) Serve() {
 	postRestMux.HandleFunc("/rest/db/prio", s.postDBPrio)                          // folder file [perpage] [page]
 	postRestMux.HandleFunc("/rest/db/ignores", s.postDBIgnores)                    // folder
 	postRestMux.HandleFunc("/rest/db/override", s.postDBOverride)                  // folder
+	postRestMux.HandleFunc("/rest/db/revert", s.postDBRevert)                      // folder
 	postRestMux.HandleFunc("/rest/db/scan", s.postDBScan)                          // folder [sub...] [delay]
+	postRestMux.HandleFunc("/rest/folder/versions", s.postFolderVersionsRestore)   // folder <body>
 	postRestMux.HandleFunc("/rest/system/config", s.postSystemConfig)              // <body>
 	postRestMux.HandleFunc("/rest/system/error", s.postSystemError)                // <body>
 	postRestMux.HandleFunc("/rest/system/error/clear", s.postSystemErrorClear)     // -
@@ -295,6 +315,7 @@ func (s *apiService) Serve() {
 	debugMux.HandleFunc("/rest/debug/httpmetrics", s.getSystemHTTPMetrics)
 	debugMux.HandleFunc("/rest/debug/cpuprof", s.getCPUProf) // duration
 	debugMux.HandleFunc("/rest/debug/heapprof", s.getHeapProf)
+	debugMux.HandleFunc("/rest/debug/support", s.getSupportBundle)
 	getRestMux.Handle("/rest/debug/", s.whenDebugging(debugMux))

 	// A handler that splits requests between the two above and disables
@@ -322,8 +343,8 @@ func (s *apiService) Serve() {
 	handler = withDetailsMiddleware(s.id, handler)

 	// Wrap everything in basic auth, if user/password is set.
-	if len(guiCfg.User) > 0 && len(guiCfg.Password) > 0 {
-		handler = basicAuthAndSessionMiddleware("sessionid-"+s.id.String()[:5], guiCfg, handler)
+	if guiCfg.IsAuthEnabled() {
+		handler = basicAuthAndSessionMiddleware("sessionid-"+s.id.String()[:5], guiCfg, s.cfg.LDAP(), handler)
 	}

 	// Redirect to HTTPS if we are supposed to
@@ -332,7 +353,7 @@ func (s *apiService) Serve() {
 	}

 	// Add the CORS handling
-	handler = corsMiddleware(handler)
+	handler = corsMiddleware(handler, guiCfg.InsecureAllowFrameLoading)

 	if addressIsLocalhost(guiCfg.Address()) && !guiCfg.InsecureSkipHostCheck {
 		// Verify source host
@@ -398,6 +419,9 @@ func (s *apiService) String() string {
 }

 func (s *apiService) VerifyConfiguration(from, to config.Configuration) error {
+	if to.GUI.Network() != "tcp" {
+		return nil
+	}
 	_, err := net.ResolveTCPAddr("tcp", to.GUI.Address())
 	return err
 }
@@ -459,7 +483,7 @@ func debugMiddleware(h http.Handler) http.Handler {
 	})
 }

-func corsMiddleware(next http.Handler) http.Handler {
+func corsMiddleware(next http.Handler, allowFrameLoading bool) http.Handler {
 	// Handle CORS headers and CORS OPTIONS request.
 	// CORS OPTIONS request are typically sent by browser during AJAX preflight
 	// when the browser initiate a POST request.
@@ -486,9 +510,29 @@ func corsMiddleware(next http.Handler) http.Handler {
 			return
 		}

+		// Other security related headers that should be present.
+		// https://www.owasp.org/index.php/Security_Headers
+
+		if !allowFrameLoading {
+			// We don't want to be rendered in an <iframe>,
+			// <frame> or <object>. (Unless we do it ourselves.
+			// This is also an escape hatch for people who serve
+			// Syncthing GUI as part of their own website
+			// through a proxy, so they don't need to set the
+			// allowFrameLoading bool.)
+			w.Header().Set("X-Frame-Options", "SAMEORIGIN")
+		}
+
+		// If the browser senses an XSS attack it's allowed to take
+		// action. (How this would not always be the default I
+		// don't fully understand.)
+		w.Header().Set("X-XSS-Protection", "1; mode=block")
+
+		// Our content type headers are correct. Don't guess.
+		w.Header().Set("X-Content-Type-Options", "nosniff")
+
 		// For everything else, pass to the next handler
 		next.ServeHTTP(w, r)
-		return
 	})
 }

@@ -525,7 +569,7 @@ func noCacheMiddleware(h http.Handler) http.Handler {

 func withDetailsMiddleware(id protocol.DeviceID, h http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("X-Syncthing-Version", Version)
+		w.Header().Set("X-Syncthing-Version", build.Version)
 		w.Header().Set("X-Syncthing-ID", id.String())
 		h.ServeHTTP(w, r)
 	})
@@ -549,7 +593,7 @@ func (s *apiService) whenDebugging(h http.Handler) http.Handler {
 			return
 		}

-		http.Error(w, "Debugging disabled", http.StatusBadRequest)
+		http.Error(w, "Debugging disabled", http.StatusForbidden)
 	})
 }

@@ -566,12 +610,15 @@ func (s *apiService) getJSMetadata(w http.ResponseWriter, r *http.Request) {
 }

 func (s *apiService) getSystemVersion(w http.ResponseWriter, r *http.Request) {
-	sendJSON(w, map[string]string{
-		"version":     Version,
-		"codename":    Codename,
-		"longVersion": LongVersion,
+	sendJSON(w, map[string]interface{}{
+		"version":     build.Version,
+		"codename":    build.Codename,
+		"longVersion": build.LongVersion,
 		"os":          runtime.GOOS,
 		"arch":        runtime.GOARCH,
+		"isBeta":      build.IsBeta,
+		"isCandidate": build.IsCandidate,
+		"isRelease":   build.IsRelease,
 	})
 }

@@ -629,38 +676,65 @@ func (s *apiService) getDBCompletion(w http.ResponseWriter, r *http.Request) {
 		return
 	}

-	comp := s.model.Completion(device, folder)
-	sendJSON(w, map[string]interface{}{
+	sendJSON(w, jsonCompletion(s.model.Completion(device, folder)))
+}
+
+func jsonCompletion(comp model.FolderCompletion) map[string]interface{} {
+	return map[string]interface{}{
 		"completion":  comp.CompletionPct,
 		"needBytes":   comp.NeedBytes,
+		"needItems":   comp.NeedItems,
 		"globalBytes": comp.GlobalBytes,
 		"needDeletes": comp.NeedDeletes,
-	})
+	}
 }

 func (s *apiService) getDBStatus(w http.ResponseWriter, r *http.Request) {
 	qs := r.URL.Query()
 	folder := qs.Get("folder")
-	sendJSON(w, folderSummary(s.cfg, s.model, folder))
+	if sum, err := folderSummary(s.cfg, s.model, folder); err != nil {
+		http.Error(w, err.Error(), http.StatusNotFound)
+	} else {
+		sendJSON(w, sum)
+	}
 }

-func folderSummary(cfg configIntf, m modelIntf, folder string) map[string]interface{} {
+func folderSummary(cfg configIntf, m modelIntf, folder string) (map[string]interface{}, error) {
 	var res = make(map[string]interface{})

+	errors, err := m.FolderErrors(folder)
+	if err != nil && err != model.ErrFolderPaused {
+		// Stats from the db can still be obtained if the folder is just paused
+		return nil, err
+	}
+	res["errors"] = len(errors)
+	res["pullErrors"] = len(errors) // deprecated
+
 	res["invalid"] = "" // Deprecated, retains external API for now

 	global := m.GlobalSize(folder)
-	res["globalFiles"], res["globalDirectories"], res["globalSymlinks"], res["globalDeleted"], res["globalBytes"] = global.Files, global.Directories, global.Symlinks, global.Deleted, global.Bytes
+	res["globalFiles"], res["globalDirectories"], res["globalSymlinks"], res["globalDeleted"], res["globalBytes"], res["globalTotalItems"] = global.Files, global.Directories, global.Symlinks, global.Deleted, global.Bytes, global.TotalItems()

 	local := m.LocalSize(folder)
-	res["localFiles"], res["localDirectories"], res["localSymlinks"], res["localDeleted"], res["localBytes"] = local.Files, local.Directories, local.Symlinks, local.Deleted, local.Bytes
+	res["localFiles"], res["localDirectories"], res["localSymlinks"], res["localDeleted"], res["localBytes"], res["localTotalItems"] = local.Files, local.Directories, local.Symlinks, local.Deleted, local.Bytes, local.TotalItems()

 	need := m.NeedSize(folder)
-	res["needFiles"], res["needDirectories"], res["needSymlinks"], res["needDeletes"], res["needBytes"] = need.Files, need.Directories, need.Symlinks, need.Deleted, need.Bytes
+	res["needFiles"], res["needDirectories"], res["needSymlinks"], res["needDeletes"], res["needBytes"], res["needTotalItems"] = need.Files, need.Directories, need.Symlinks, need.Deleted, need.Bytes, need.TotalItems()
+
+	if cfg.Folders()[folder].Type == config.FolderTypeReceiveOnly {
+		// Add statistics for things that have changed locally in a receive
+		// only folder.
+		ro := m.ReceiveOnlyChangedSize(folder)
+		res["receiveOnlyChangedFiles"] = ro.Files
+		res["receiveOnlyChangedDirectories"] = ro.Directories
+		res["receiveOnlyChangedSymlinks"] = ro.Symlinks
+		res["receiveOnlyChangedDeletes"] = ro.Deleted
+		res["receiveOnlyChangedBytes"] = ro.Bytes
+		res["receiveOnlyTotalItems"] = ro.TotalItems()
+	}

 	res["inSyncFiles"], res["inSyncBytes"] = global.Files-need.Files, global.Bytes-need.Bytes

-	var err error
 	res["state"], res["stateChanged"], err = m.State(folder)
 	if err != nil {
 		res["error"] = err.Error()
@@ -681,7 +755,12 @@ func folderSummary(cfg configIntf, m modelIntf, folder string) map[string]interf
 		}
 	}

-	return res
+	err = m.WatchError(folder)
+	if err != nil {
+		res["watchError"] = err.Error()
+	}
+
+	return res, nil
 }

 func (s *apiService) postDBOverride(w http.ResponseWriter, r *http.Request) {
@@ -690,11 +769,13 @@ func (s *apiService) postDBOverride(w http.ResponseWriter, r *http.Request) {
 	go s.model.Override(folder)
 }

-func (s *apiService) getDBNeed(w http.ResponseWriter, r *http.Request) {
-	qs := r.URL.Query()
-
-	folder := qs.Get("folder")
+func (s *apiService) postDBRevert(w http.ResponseWriter, r *http.Request) {
+	var qs = r.URL.Query()
+	var folder = qs.Get("folder")
+	go s.model.Revert(folder)
+}

+func getPagingParams(qs url.Values) (int, int) {
 	page, err := strconv.Atoi(qs.Get("page"))
 	if err != nil || page < 1 {
 		page = 1
@@ -703,20 +784,68 @@ func (s *apiService) getDBNeed(w http.ResponseWriter, r *http.Request) {
 	if err != nil || perpage < 1 {
 		perpage = 1 << 16
 	}
+	return page, perpage
+}

-	progress, queued, rest, total := s.model.NeedFolderFiles(folder, page, perpage)
+func (s *apiService) getDBNeed(w http.ResponseWriter, r *http.Request) {
+	qs := r.URL.Query()
+
+	folder := qs.Get("folder")
+
+	page, perpage := getPagingParams(qs)
+
+	progress, queued, rest := s.model.NeedFolderFiles(folder, page, perpage)

 	// Convert the struct to a more loose structure, and inject the size.
 	sendJSON(w, map[string]interface{}{
-		"progress": s.toNeedSlice(progress),
-		"queued":   s.toNeedSlice(queued),
-		"rest":     s.toNeedSlice(rest),
-		"total":    total,
+		"progress": toJsonFileInfoSlice(progress),
+		"queued":   toJsonFileInfoSlice(queued),
+		"rest":     toJsonFileInfoSlice(rest),
 		"page":     page,
 		"perpage":  perpage,
 	})
 }

+func (s *apiService) getDBRemoteNeed(w http.ResponseWriter, r *http.Request) {
+	qs := r.URL.Query()
+
+	folder := qs.Get("folder")
+	device := qs.Get("device")
+	deviceID, err := protocol.DeviceIDFromString(device)
+	if err != nil {
+		http.Error(w, err.Error(), 500)
+		return
+	}
+
+	page, perpage := getPagingParams(qs)
+
+	if files, err := s.model.RemoteNeedFolderFiles(deviceID, folder, page, perpage); err != nil {
+		http.Error(w, err.Error(), http.StatusNotFound)
+	} else {
+		sendJSON(w, map[string]interface{}{
+			"files":   toJsonFileInfoSlice(files),
+			"page":    page,
+			"perpage": perpage,
+		})
+	}
+}
+
+func (s *apiService) getDBLocalChanged(w http.ResponseWriter, r *http.Request) {
+	qs := r.URL.Query()
+
+	folder := qs.Get("folder")
+
+	page, perpage := getPagingParams(qs)
+
+	files := s.model.LocalChangedFiles(folder, page, perpage)
+
+	sendJSON(w, map[string]interface{}{
+		"files":   toJsonFileInfoSlice(files),
+		"page":    page,
+		"perpage": perpage,
+	})
+}
+
 func (s *apiService) getSystemConnections(w http.ResponseWriter, r *http.Request) {
 	sendJSON(w, s.model.ConnectionStats())
 }
@@ -742,7 +871,7 @@ func (s *apiService) getDBFile(w http.ResponseWriter, r *http.Request) {
 		return
 	}

-	av := s.model.Availability(folder, file, protocol.Vector{}, protocol.BlockInfo{})
+	av := s.model.Availability(folder, gf, protocol.BlockInfo{})
 	sendJSON(w, map[string]interface{}{
 		"global":       jsonFileInfo(gf),
 		"local":        jsonFileInfo(lf),
@@ -767,7 +896,7 @@ func (s *apiService) postSystemConfig(w http.ResponseWriter, r *http.Request) {
 	}

 	if to.GUI.Password != s.cfg.GUI().Password {
-		if to.GUI.Password != "" {
+		if to.GUI.Password != "" && !bcryptExpr.MatchString(to.GUI.Password) {
 			hash, err := bcrypt.GenerateFromPassword([]byte(to.GUI.Password), 0)
 			if err != nil {
 				l.Warnln("bcrypting password:", err)
@@ -779,24 +908,15 @@ func (s *apiService) postSystemConfig(w http.ResponseWriter, r *http.Request) {
 		}
 	}

-	// Fixup usage reporting settings
+	// Activate and save. Wait for the configuration to become active before
+	// completing the request.

-	if curAcc := s.cfg.Options().URAccepted; to.Options.URAccepted > curAcc {
-		// UR was enabled
-		to.Options.URAccepted = usageReportVersion
-		to.Options.URUniqueID = rand.String(8)
-	} else if to.Options.URAccepted < curAcc {
-		// UR was disabled
-		to.Options.URAccepted = -1
-		to.Options.URUniqueID = ""
-	}
-
-	// Activate and save
-
-	if err := s.cfg.Replace(to); err != nil {
+	if wg, err := s.cfg.Replace(to); err != nil {
 		l.Warnln("Replacing config:", err)
 		http.Error(w, err.Error(), http.StatusInternalServerError)
 		return
+	} else {
+		wg.Wait()
 	}

 	if err := s.cfg.Save(); err != nil {
@@ -856,7 +976,7 @@ func (s *apiService) getSystemStatus(w http.ResponseWriter, r *http.Request) {
 	var m runtime.MemStats
 	runtime.ReadMemStats(&m)

-	tilde, _ := osutil.ExpandTilde("~")
+	tilde, _ := fs.ExpandTilde("~")
 	res := make(map[string]interface{})
 	res["myID"] = myID.String()
 	res["goroutines"] = runtime.NumGoroutine()
@@ -882,8 +1002,10 @@ func (s *apiService) getSystemStatus(w http.ResponseWriter, r *http.Request) {
 	// gives us percent
 	res["cpuPercent"] = s.cpu.Rate() / 10 / float64(runtime.NumCPU())
 	res["pathSeparator"] = string(filepath.Separator)
+	res["urVersionMax"] = usageReportVersion
 	res["uptime"] = int(time.Since(startTime).Seconds())
 	res["startTime"] = startTime
+	res["guiAddressOverridden"] = s.cfg.GUI().IsOverridden()

 	sendJSON(w, res)
 }
@@ -907,7 +1029,9 @@ func (s *apiService) postSystemErrorClear(w http.ResponseWriter, r *http.Request
 func (s *apiService) getSystemLog(w http.ResponseWriter, r *http.Request) {
 	q := r.URL.Query()
 	since, err := time.Parse(time.RFC3339, q.Get("since"))
-	l.Debugln(err)
+	if err != nil {
+		l.Debugln(err)
+	}
 	sendJSON(w, map[string][]logger.Line{
 		"messages": s.systemLog.Since(since),
 	})
@@ -916,7 +1040,9 @@ func (s *apiService) getSystemLog(w http.ResponseWriter, r *http.Request) {
 func (s *apiService) getSystemLogTxt(w http.ResponseWriter, r *http.Request) {
 	q := r.URL.Query()
 	since, err := time.Parse(time.RFC3339, q.Get("since"))
-	l.Debugln(err)
+	if err != nil {
+		l.Debugln(err)
+	}
 	w.Header().Set("Content-Type", "text/plain; charset=utf-8")

 	for _, line := range s.systemLog.Since(since) {
@@ -924,6 +1050,113 @@ func (s *apiService) getSystemLogTxt(w http.ResponseWriter, r *http.Request) {
 	}
 }

+type fileEntry struct {
+	name string
+	data []byte
+}
+
+func (s *apiService) getSupportBundle(w http.ResponseWriter, r *http.Request) {
+	var files []fileEntry
+
+	// Redacted configuration as a JSON
+	if jsonConfig, err := json.MarshalIndent(getRedactedConfig(s), "", "  "); err == nil {
+		files = append(files, fileEntry{name: "config.json.txt", data: jsonConfig})
+	} else {
+		l.Warnln("Support bundle: failed to create config.json:", err)
+	}
+
+	// Log as a text
+	var buflog bytes.Buffer
+	for _, line := range s.systemLog.Since(time.Time{}) {
+		fmt.Fprintf(&buflog, "%s: %s\n", line.When.Format(time.RFC3339), line.Message)
+	}
+	files = append(files, fileEntry{name: "log-inmemory.txt", data: buflog.Bytes()})
+
+	// Errors as a JSON
+	if errs := s.guiErrors.Since(time.Time{}); len(errs) > 0 {
+		if jsonError, err := json.MarshalIndent(errs, "", "  "); err != nil {
+			files = append(files, fileEntry{name: "errors.json.txt", data: jsonError})
+		} else {
+			l.Warnln("Support bundle: failed to create errors.json:", err)
+		}
+	}
+
+	// Panic files
+	if panicFiles, err := filepath.Glob(filepath.Join(locations.GetBaseDir(locations.ConfigBaseDir), "panic*")); err == nil {
+		for _, f := range panicFiles {
+			if panicFile, err := ioutil.ReadFile(f); err != nil {
+				l.Warnf("Support bundle: failed to load %s: %s", filepath.Base(f), err)
+			} else {
+				files = append(files, fileEntry{name: filepath.Base(f), data: panicFile})
+			}
+		}
+	}
+
+	// Archived log (default on Windows)
+	if logFile, err := ioutil.ReadFile(locations.Get(locations.LogFile)); err == nil {
+		files = append(files, fileEntry{name: "log-ondisk.txt", data: logFile})
+	}
+
+	// Version and platform information as a JSON
+	if versionPlatform, err := json.MarshalIndent(map[string]string{
+		"now":         time.Now().Format(time.RFC3339),
+		"version":     build.Version,
+		"codename":    build.Codename,
+		"longVersion": build.LongVersion,
+		"os":          runtime.GOOS,
+		"arch":        runtime.GOARCH,
+	}, "", "  "); err == nil {
+		files = append(files, fileEntry{name: "version-platform.json.txt", data: versionPlatform})
+	} else {
+		l.Warnln("Failed to create versionPlatform.json: ", err)
+	}
+
+	// Report Data as a JSON
+	if usageReportingData, err := json.MarshalIndent(reportData(s.cfg, s.model, s.connectionsService, usageReportVersion, true), "", "  "); err != nil {
+		l.Warnln("Support bundle: failed to create versionPlatform.json:", err)
+	} else {
+		files = append(files, fileEntry{name: "usage-reporting.json.txt", data: usageReportingData})
+	}
+
+	// Heap and CPU Proofs as a pprof extension
+	var heapBuffer, cpuBuffer bytes.Buffer
+	filename := fmt.Sprintf("syncthing-heap-%s-%s-%s-%s.pprof", runtime.GOOS, runtime.GOARCH, build.Version, time.Now().Format("150405")) // hhmmss
+	runtime.GC()
+	if err := pprof.WriteHeapProfile(&heapBuffer); err == nil {
+		files = append(files, fileEntry{name: filename, data: heapBuffer.Bytes()})
+	}
+
+	const duration = 4 * time.Second
+	filename = fmt.Sprintf("syncthing-cpu-%s-%s-%s-%s.pprof", runtime.GOOS, runtime.GOARCH, build.Version, time.Now().Format("150405")) // hhmmss
+	if err := pprof.StartCPUProfile(&cpuBuffer); err == nil {
+		time.Sleep(duration)
+		pprof.StopCPUProfile()
+		files = append(files, fileEntry{name: filename, data: cpuBuffer.Bytes()})
+	}
+
+	// Add buffer files to buffer zip
+	var zipFilesBuffer bytes.Buffer
+	if err := writeZip(&zipFilesBuffer, files); err != nil {
+		l.Warnln("Support bundle: failed to create support bundle zip:", err)
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+
+	// Set zip file name and path
+	zipFileName := fmt.Sprintf("support-bundle-%s-%s.zip", s.id.Short().String(), time.Now().Format("2006-01-02T150405"))
+	zipFilePath := filepath.Join(locations.GetBaseDir(locations.ConfigBaseDir), zipFileName)
+
+	// Write buffer zip to local zip file (back up)
+	if err := ioutil.WriteFile(zipFilePath, zipFilesBuffer.Bytes(), 0600); err != nil {
+		l.Warnln("Support bundle: support bundle zip could not be created:", err)
+	}
+
+	// Serve the buffer zip to client for download
+	w.Header().Set("Content-Type", "application/zip")
+	w.Header().Set("Content-Disposition", "attachment; filename="+zipFileName)
+	io.Copy(w, &zipFilesBuffer)
+}
+
 func (s *apiService) getSystemHTTPMetrics(w http.ResponseWriter, r *http.Request) {
 	stats := make(map[string]interface{})
 	metrics.Each(func(name string, intf interface{}) {
@@ -960,7 +1193,11 @@ func (s *apiService) getSystemDiscovery(w http.ResponseWriter, r *http.Request)
 }

 func (s *apiService) getReport(w http.ResponseWriter, r *http.Request) {
-	sendJSON(w, reportData(s.cfg, s.model))
+	version := usageReportVersion
+	if val, _ := strconv.Atoi(r.URL.Query().Get("version")); val > 0 {
+		version = val
+	}
+	sendJSON(w, reportData(s.cfg, s.model, s.connectionsService, version, true))
 }

 func (s *apiService) getRandomString(w http.ResponseWriter, r *http.Request) {
@@ -1088,16 +1325,16 @@ func (s *apiService) getSystemUpgrade(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	opts := s.cfg.Options()
-	rel, err := upgrade.LatestRelease(opts.ReleasesURL, Version, opts.UpgradeToPreReleases)
+	rel, err := upgrade.LatestRelease(opts.ReleasesURL, build.Version, opts.UpgradeToPreReleases)
 	if err != nil {
 		http.Error(w, err.Error(), 500)
 		return
 	}
 	res := make(map[string]interface{})
-	res["running"] = Version
+	res["running"] = build.Version
 	res["latest"] = rel.Tag
-	res["newer"] = upgrade.CompareVersions(rel.Tag, Version) == upgrade.Newer
-	res["majorNewer"] = upgrade.CompareVersions(rel.Tag, Version) == upgrade.MajorNewer
+	res["newer"] = upgrade.CompareVersions(rel.Tag, build.Version) == upgrade.Newer
+	res["majorNewer"] = upgrade.CompareVersions(rel.Tag, build.Version) == upgrade.MajorNewer

 	sendJSON(w, res)
 }
@@ -1130,14 +1367,14 @@ func (s *apiService) getLang(w http.ResponseWriter, r *http.Request) {

 func (s *apiService) postSystemUpgrade(w http.ResponseWriter, r *http.Request) {
 	opts := s.cfg.Options()
-	rel, err := upgrade.LatestRelease(opts.ReleasesURL, Version, opts.UpgradeToPreReleases)
+	rel, err := upgrade.LatestRelease(opts.ReleasesURL, build.Version, opts.UpgradeToPreReleases)
 	if err != nil {
 		l.Warnln("getting latest release:", err)
 		http.Error(w, err.Error(), 500)
 		return
 	}

-	if upgrade.CompareVersions(rel.Tag, Version) > upgrade.Equal {
+	if upgrade.CompareVersions(rel.Tag, build.Version) > upgrade.Equal {
 		err = upgrade.To(rel)
 		if err != nil {
 			l.Warnln("upgrading:", err)
@@ -1180,7 +1417,7 @@ func (s *apiService) makeDevicePauseHandler(paused bool) http.HandlerFunc {
 			cfgs = append(cfgs, cfg)
 		}

-		if err := s.cfg.SetDevices(cfgs); err != nil {
+		if _, err := s.cfg.SetDevices(cfgs); err != nil {
 			http.Error(w, err.Error(), 500)
 		}
 	}
@@ -1239,7 +1476,7 @@ func (s *apiService) getPeerCompletion(w http.ResponseWriter, r *http.Request) {
 	for _, folder := range s.cfg.Folders() {
 		for _, device := range folder.DeviceIDs() {
 			deviceStr := device.String()
-			if s.model.ConnectedTo(device) {
+			if _, ok := s.model.Connection(device); ok {
 				tot[deviceStr] += s.model.Completion(device, folder.ID).CompletionPct
 			} else {
 				tot[deviceStr] = 0
@@ -1256,32 +1493,148 @@ func (s *apiService) getPeerCompletion(w http.ResponseWriter, r *http.Request) {
 	sendJSON(w, comp)
 }

-func (s *apiService) getSystemBrowse(w http.ResponseWriter, r *http.Request) {
+func (s *apiService) getFolderVersions(w http.ResponseWriter, r *http.Request) {
 	qs := r.URL.Query()
-	current := qs.Get("current")
-	if current == "" {
-		if roots, err := osutil.GetFilesystemRoots(); err == nil {
-			sendJSON(w, roots)
-		} else {
-			http.Error(w, err.Error(), 500)
-		}
+	versions, err := s.model.GetFolderVersions(qs.Get("folder"))
+	if err != nil {
+		http.Error(w, err.Error(), 500)
 		return
 	}
-	search, _ := osutil.ExpandTilde(current)
-	pathSeparator := string(os.PathSeparator)
-	if strings.HasSuffix(current, pathSeparator) && !strings.HasSuffix(search, pathSeparator) {
-		search = search + pathSeparator
+	sendJSON(w, versions)
+}
+
+func (s *apiService) postFolderVersionsRestore(w http.ResponseWriter, r *http.Request) {
+	qs := r.URL.Query()
+
+	bs, err := ioutil.ReadAll(r.Body)
+	r.Body.Close()
+	if err != nil {
+		http.Error(w, err.Error(), 500)
+		return
 	}
-	subdirectories, _ := osutil.Glob(search + "*")
-	ret := make([]string, 0, len(subdirectories))
-	for _, subdirectory := range subdirectories {
-		info, err := os.Stat(subdirectory)
-		if err == nil && info.IsDir() {
-			ret = append(ret, subdirectory+pathSeparator)
+
+	var versions map[string]time.Time
+	err = json.Unmarshal(bs, &versions)
+	if err != nil {
+		http.Error(w, err.Error(), 500)
+		return
+	}
+
+	ferr, err := s.model.RestoreFolderVersions(qs.Get("folder"), versions)
+	if err != nil {
+		http.Error(w, err.Error(), 500)
+		return
+	}
+	sendJSON(w, ferr)
+}
+
+func (s *apiService) getFolderErrors(w http.ResponseWriter, r *http.Request) {
+	qs := r.URL.Query()
+	folder := qs.Get("folder")
+	page, perpage := getPagingParams(qs)
+
+	errors, err := s.model.FolderErrors(folder)
+
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusNotFound)
+		return
+	}
+
+	start := (page - 1) * perpage
+	if start >= len(errors) {
+		errors = nil
+	} else {
+		errors = errors[start:]
+		if perpage < len(errors) {
+			errors = errors[:perpage]
 		}
 	}

-	sendJSON(w, ret)
+	sendJSON(w, map[string]interface{}{
+		"folder":  folder,
+		"errors":  errors,
+		"page":    page,
+		"perpage": perpage,
+	})
+}
+
+func (s *apiService) getSystemBrowse(w http.ResponseWriter, r *http.Request) {
+	qs := r.URL.Query()
+	current := qs.Get("current")
+
+	// Default value or in case of error unmarshalling ends up being basic fs.
+	var fsType fs.FilesystemType
+	fsType.UnmarshalText([]byte(qs.Get("filesystem")))
+
+	sendJSON(w, browseFiles(current, fsType))
+}
+
+const (
+	matchExact int = iota
+	matchCaseIns
+	noMatch
+)
+
+func checkPrefixMatch(s, prefix string) int {
+	if strings.HasPrefix(s, prefix) {
+		return matchExact
+	}
+
+	if strings.HasPrefix(strings.ToLower(s), strings.ToLower(prefix)) {
+		return matchCaseIns
+	}
+
+	return noMatch
+}
+
+func browseFiles(current string, fsType fs.FilesystemType) []string {
+	if current == "" {
+		filesystem := fs.NewFilesystem(fsType, "")
+		if roots, err := filesystem.Roots(); err == nil {
+			return roots
+		}
+		return nil
+	}
+	search, _ := fs.ExpandTilde(current)
+	pathSeparator := string(fs.PathSeparator)
+
+	if strings.HasSuffix(current, pathSeparator) && !strings.HasSuffix(search, pathSeparator) {
+		search = search + pathSeparator
+	}
+	searchDir := filepath.Dir(search)
+
+	// The searchFile should be the last component of search, or empty if it
+	// ends with a path separator
+	var searchFile string
+	if !strings.HasSuffix(search, pathSeparator) {
+		searchFile = filepath.Base(search)
+	}
+
+	fs := fs.NewFilesystem(fsType, searchDir)
+
+	subdirectories, _ := fs.DirNames(".")
+
+	exactMatches := make([]string, 0, len(subdirectories))
+	caseInsMatches := make([]string, 0, len(subdirectories))
+
+	for _, subdirectory := range subdirectories {
+		info, err := fs.Stat(subdirectory)
+		if err != nil || !info.IsDir() {
+			continue
+		}
+
+		switch checkPrefixMatch(subdirectory, searchFile) {
+		case matchExact:
+			exactMatches = append(exactMatches, filepath.Join(searchDir, subdirectory)+pathSeparator)
+		case matchCaseIns:
+			caseInsMatches = append(caseInsMatches, filepath.Join(searchDir, subdirectory)+pathSeparator)
+		}
+	}
+
+	// sort to return matches in deterministic order (don't depend on file system order)
+	sort.Strings(exactMatches)
+	sort.Strings(caseInsMatches)
+	return append(exactMatches, caseInsMatches...)
 }

 func (s *apiService) getCPUProf(w http.ResponseWriter, r *http.Request) {
@@ -1290,18 +1643,19 @@ func (s *apiService) getCPUProf(w http.ResponseWriter, r *http.Request) {
 		duration = 30 * time.Second
 	}

-	filename := fmt.Sprintf("syncthing-cpu-%s-%s-%s-%s.pprof", runtime.GOOS, runtime.GOARCH, Version, time.Now().Format("150405")) // hhmmss
+	filename := fmt.Sprintf("syncthing-cpu-%s-%s-%s-%s.pprof", runtime.GOOS, runtime.GOARCH, build.Version, time.Now().Format("150405")) // hhmmss

 	w.Header().Set("Content-Type", "application/octet-stream")
 	w.Header().Set("Content-Disposition", "attachment; filename="+filename)

-	pprof.StartCPUProfile(w)
-	time.Sleep(duration)
-	pprof.StopCPUProfile()
+	if err := pprof.StartCPUProfile(w); err == nil {
+		time.Sleep(duration)
+		pprof.StopCPUProfile()
+	}
 }

 func (s *apiService) getHeapProf(w http.ResponseWriter, r *http.Request) {
-	filename := fmt.Sprintf("syncthing-heap-%s-%s-%s-%s.pprof", runtime.GOOS, runtime.GOARCH, Version, time.Now().Format("150405")) // hhmmss
+	filename := fmt.Sprintf("syncthing-heap-%s-%s-%s-%s.pprof", runtime.GOOS, runtime.GOARCH, build.Version, time.Now().Format("150405")) // hhmmss

 	w.Header().Set("Content-Type", "application/octet-stream")
 	w.Header().Set("Content-Disposition", "attachment; filename="+filename)
@@ -1310,7 +1664,7 @@ func (s *apiService) getHeapProf(w http.ResponseWriter, r *http.Request) {
 	pprof.WriteHeapProfile(w)
 }

-func (s *apiService) toNeedSlice(fs []db.FileInfoTruncated) []jsonDBFileInfo {
+func toJsonFileInfoSlice(fs []db.FileInfoTruncated) []jsonDBFileInfo {
 	res := make([]jsonDBFileInfo, len(fs))
 	for i, f := range fs {
 		res[i] = jsonDBFileInfo(f)
@@ -1329,12 +1683,16 @@ func (f jsonFileInfo) MarshalJSON() ([]byte, error) {
 		"size":          f.Size,
 		"permissions":   fmt.Sprintf("%#o", f.Permissions),
 		"deleted":       f.Deleted,
-		"invalid":       f.Invalid,
+		"invalid":       protocol.FileInfo(f).IsInvalid(),
+		"ignored":       protocol.FileInfo(f).IsIgnored(),
+		"mustRescan":    protocol.FileInfo(f).MustRescan(),
 		"noPermissions": f.NoPermissions,
 		"modified":      protocol.FileInfo(f).ModTime(),
+		"modifiedBy":    f.ModifiedBy.String(),
 		"sequence":      f.Sequence,
 		"numBlocks":     len(f.Blocks),
 		"version":       jsonVersionVector(f.Version),
+		"localFlags":    f.LocalFlags,
 	})
 }

@@ -1343,14 +1701,20 @@ type jsonDBFileInfo db.FileInfoTruncated
 func (f jsonDBFileInfo) MarshalJSON() ([]byte, error) {
 	return json.Marshal(map[string]interface{}{
 		"name":          f.Name,
-		"type":          f.Type,
+		"type":          f.Type.String(),
 		"size":          f.Size,
 		"permissions":   fmt.Sprintf("%#o", f.Permissions),
 		"deleted":       f.Deleted,
-		"invalid":       f.Invalid,
+		"invalid":       db.FileInfoTruncated(f).IsInvalid(),
+		"ignored":       db.FileInfoTruncated(f).IsIgnored(),
+		"mustRescan":    db.FileInfoTruncated(f).MustRescan(),
 		"noPermissions": f.NoPermissions,
 		"modified":      db.FileInfoTruncated(f).ModTime(),
+		"modifiedBy":    f.ModifiedBy.String(),
 		"sequence":      f.Sequence,
+		"numBlocks":     nil, // explicitly unknown
+		"version":       jsonVersionVector(f.Version),
+		"localFlags":    f.LocalFlags,
 	})
 }

@@ -1394,9 +1758,14 @@ func addressIsLocalhost(addr string) bool {
 		host = addr
 	}
 	switch strings.ToLower(host) {
-	case "127.0.0.1", "::1", "localhost":
+	case "localhost", "localhost.":
 		return true
 	default:
-		return false
+		ip := net.ParseIP(host)
+		if ip == nil {
+			// not an IP address
+			return false
+		}
+		return ip.IsLoopback()
 	}
 }
--- a/cmd/syncthing/gui_auth.go
+++ b/cmd/syncthing/gui_auth.go
@@ -8,7 +8,9 @@ package main

 import (
 	"bytes"
+	"crypto/tls"
 	"encoding/base64"
+	"fmt"
 	"net/http"
 	"strings"
 	"time"
@@ -18,6 +20,7 @@ import (
 	"github.com/syncthing/syncthing/lib/rand"
 	"github.com/syncthing/syncthing/lib/sync"
 	"golang.org/x/crypto/bcrypt"
+	ldap "gopkg.in/ldap.v2"
 )

 var (
@@ -32,9 +35,9 @@ func emitLoginAttempt(success bool, username string) {
 	})
 }

-func basicAuthAndSessionMiddleware(cookieName string, cfg config.GUIConfiguration, next http.Handler) http.Handler {
+func basicAuthAndSessionMiddleware(cookieName string, guiCfg config.GUIConfiguration, ldapCfg config.LDAPConfiguration, next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if cfg.IsValidAPIKey(r.Header.Get("X-API-Key")) {
+		if guiCfg.IsValidAPIKey(r.Header.Get("X-API-Key")) {
 			next.ServeHTTP(w, r)
 			return
 		}
@@ -77,42 +80,25 @@ func basicAuthAndSessionMiddleware(cookieName string, cfg config.GUIConfiguratio
 			return
 		}

-		// Check if the username is correct, assuming it was sent as UTF-8
 		username := string(fields[0])
-		if username == cfg.User {
-			goto usernameOK
+		password := string(fields[1])
+
+		authOk := auth(username, password, guiCfg, ldapCfg)
+		if !authOk {
+			usernameIso := string(iso88591ToUTF8([]byte(username)))
+			passwordIso := string(iso88591ToUTF8([]byte(password)))
+			authOk = auth(usernameIso, passwordIso, guiCfg, ldapCfg)
+			if authOk {
+				username = usernameIso
+			}
 		}

-		// ... check it again, converting it from assumed ISO-8859-1 to UTF-8
-		username = string(iso88591ToUTF8(fields[0]))
-		if username == cfg.User {
-			goto usernameOK
+		if !authOk {
+			emitLoginAttempt(false, username)
+			error()
+			return
 		}

-		// Neither of the possible interpretations match the configured username
-		emitLoginAttempt(false, username)
-		error()
-		return
-
-	usernameOK:
-		// Check password as given (assumes UTF-8 encoding)
-		password := fields[1]
-		if err := bcrypt.CompareHashAndPassword([]byte(cfg.Password), password); err == nil {
-			goto passwordOK
-		}
-
-		// ... check it again, converting it from assumed ISO-8859-1 to UTF-8
-		password = iso88591ToUTF8(password)
-		if err := bcrypt.CompareHashAndPassword([]byte(cfg.Password), password); err == nil {
-			goto passwordOK
-		}
-
-		// Neither of the attempts to verify the password checked out
-		emitLoginAttempt(false, username)
-		error()
-		return
-
-	passwordOK:
 		sessionid := rand.String(32)
 		sessionsMut.Lock()
 		sessions[sessionid] = true
@@ -128,6 +114,54 @@ func basicAuthAndSessionMiddleware(cookieName string, cfg config.GUIConfiguratio
 	})
 }

+func auth(username string, password string, guiCfg config.GUIConfiguration, ldapCfg config.LDAPConfiguration) bool {
+	if guiCfg.AuthMode == config.AuthModeLDAP {
+		return authLDAP(username, password, ldapCfg)
+	} else {
+		return authStatic(username, password, guiCfg.User, guiCfg.Password)
+	}
+}
+
+func authStatic(username string, password string, configUser string, configPassword string) bool {
+	configPasswordBytes := []byte(configPassword)
+	passwordBytes := []byte(password)
+	return bcrypt.CompareHashAndPassword(configPasswordBytes, passwordBytes) == nil && username == configUser
+}
+
+func authLDAP(username string, password string, cfg config.LDAPConfiguration) bool {
+	address := cfg.Address
+	var connection *ldap.Conn
+	var err error
+	if cfg.Transport == config.LDAPTransportTLS {
+		connection, err = ldap.DialTLS("tcp", address, &tls.Config{InsecureSkipVerify: cfg.InsecureSkipVerify})
+	} else {
+		connection, err = ldap.Dial("tcp", address)
+	}
+
+	if err != nil {
+		l.Warnln("LDAP Dial:", err)
+		return false
+	}
+
+	if cfg.Transport == config.LDAPTransportStartTLS {
+		err = connection.StartTLS(&tls.Config{InsecureSkipVerify: cfg.InsecureSkipVerify})
+		if err != nil {
+			l.Warnln("LDAP Start TLS:", err)
+			return false
+		}
+	}
+
+	defer connection.Close()
+
+	err = connection.Bind(fmt.Sprintf(cfg.BindDN, username), password)
+	if err != nil {
+		l.Warnln("LDAP Bind:", err)
+		return false
+	}
+
+	return true
+}
+
 // Convert an ISO-8859-1 encoded byte string to UTF-8. Works by the
 // principle that ISO-8859-1 bytes are equivalent to unicode code points,
 // that a rune slice is a list of code points, and that stringifying a slice
--- a/cmd/syncthing/gui_auth_test.go
+++ b/cmd/syncthing/gui_auth_test.go
@@ -0,0 +1,40 @@
+// Copyright (C) 2014 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"testing"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+var passwordHashBytes []byte
+
+func init() {
+	passwordHashBytes, _ = bcrypt.GenerateFromPassword([]byte("pass"), 0)
+}
+
+func TestStaticAuthOK(t *testing.T) {
+	ok := authStatic("user", "pass", "user", string(passwordHashBytes))
+	if !ok {
+		t.Fatalf("should pass auth")
+	}
+}
+
+func TestSimpleAuthUsernameFail(t *testing.T) {
+	ok := authStatic("userWRONG", "pass", "user", string(passwordHashBytes))
+	if ok {
+		t.Fatalf("should fail auth")
+	}
+}
+
+func TestStaticAuthPasswordFail(t *testing.T) {
+	ok := authStatic("user", "passWRONG", "user", string(passwordHashBytes))
+	if ok {
+		t.Fatalf("should fail auth")
+	}
+}
--- a/cmd/syncthing/gui_csrf.go
+++ b/cmd/syncthing/gui_csrf.go
@@ -14,6 +14,7 @@ import (
 	"strings"

 	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/locations"
 	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/rand"
 	"github.com/syncthing/syncthing/lib/sync"
@@ -115,7 +116,7 @@ func saveCsrfTokens() {
 	// We're ignoring errors in here. It's not super critical and there's
 	// nothing relevant we can do about them anyway...

-	name := locations[locCsrfTokens]
+	name := locations.Get(locations.CsrfTokens)
 	f, err := osutil.CreateAtomic(name)
 	if err != nil {
 		return
@@ -129,7 +130,7 @@ func saveCsrfTokens() {
 }

 func loadCsrfTokens() {
-	f, err := os.Open(locations[locCsrfTokens])
+	f, err := os.Open(locations.Get(locations.CsrfTokens))
 	if err != nil {
 		return
 	}
--- a/cmd/syncthing/gui_statics.go
+++ b/cmd/syncthing/gui_statics.go
@@ -16,6 +16,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"time"

 	"github.com/syncthing/syncthing/lib/auto"
 	"github.com/syncthing/syncthing/lib/config"
@@ -71,6 +72,8 @@ func (s *staticsServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 }

 func (s *staticsServer) serveAsset(w http.ResponseWriter, r *http.Request) {
+	w.Header().Set("Cache-Control", "no-cache, must-revalidate")
+
 	file := r.URL.Path

 	if file[0] == '/' {
@@ -89,6 +92,10 @@ func (s *staticsServer) serveAsset(w http.ResponseWriter, r *http.Request) {
 	if s.assetDir != "" {
 		p := filepath.Join(s.assetDir, theme, filepath.FromSlash(file))
 		if _, err := os.Stat(p); err == nil {
+			mtype := s.mimeTypeForFile(file)
+			if len(mtype) != 0 {
+				w.Header().Set("Content-Type", mtype)
+			}
 			http.ServeFile(w, r, p)
 			return
 		}
@@ -101,6 +108,10 @@ func (s *staticsServer) serveAsset(w http.ResponseWriter, r *http.Request) {
 		if s.assetDir != "" {
 			p := filepath.Join(s.assetDir, config.DefaultTheme, filepath.FromSlash(file))
 			if _, err := os.Stat(p); err == nil {
+				mtype := s.mimeTypeForFile(file)
+				if len(mtype) != 0 {
+					w.Header().Set("Content-Type", mtype)
+				}
 				http.ServeFile(w, r, p)
 				return
 			}
@@ -114,6 +125,26 @@ func (s *staticsServer) serveAsset(w http.ResponseWriter, r *http.Request) {
 		}
 	}

+	etag := fmt.Sprintf("%d", auto.Generated)
+	modified := time.Unix(auto.Generated, 0).UTC()
+
+	w.Header().Set("Last-Modified", modified.Format(http.TimeFormat))
+	w.Header().Set("Etag", etag)
+
+	if t, err := time.Parse(http.TimeFormat, r.Header.Get("If-Modified-Since")); err == nil {
+		if modified.Equal(t) || modified.Before(t) {
+			w.WriteHeader(http.StatusNotModified)
+			return
+		}
+	}
+
+	if match := r.Header.Get("If-None-Match"); match != "" {
+		if strings.Contains(match, etag) {
+			w.WriteHeader(http.StatusNotModified)
+			return
+		}
+	}
+
 	mtype := s.mimeTypeForFile(file)
 	if len(mtype) != 0 {
 		w.Header().Set("Content-Type", mtype)
@@ -141,17 +172,17 @@ func (s *staticsServer) serveThemes(w http.ResponseWriter, r *http.Request) {
 func (s *staticsServer) mimeTypeForFile(file string) string {
 	// We use a built in table of the common types since the system
 	// TypeByExtension might be unreliable. But if we don't know, we delegate
-	// to the system.
+	// to the system. All our files are UTF-8.
 	ext := filepath.Ext(file)
 	switch ext {
 	case ".htm", ".html":
-		return "text/html"
+		return "text/html; charset=utf-8"
 	case ".css":
-		return "text/css"
+		return "text/css; charset=utf-8"
 	case ".js":
-		return "application/javascript"
+		return "application/javascript; charset=utf-8"
 	case ".json":
-		return "application/json"
+		return "application/json; charset=utf-8"
 	case ".png":
 		return "image/png"
 	case ".ttf":
@@ -159,7 +190,7 @@ func (s *staticsServer) mimeTypeForFile(file string) string {
 	case ".woff":
 		return "application/x-font-woff"
 	case ".svg":
-		return "image/svg+xml"
+		return "image/svg+xml; charset=utf-8"
 	default:
 		return mime.TypeByExtension(ext)
 	}
--- a/cmd/syncthing/gui_test.go
+++ b/cmd/syncthing/gui_test.go
@@ -16,6 +16,8 @@ import (
 	"net"
 	"net/http"
 	"net/http/httptest"
+	"os"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"testing"
@@ -24,6 +26,7 @@ import (
 	"github.com/d4l3k/messagediff"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/sync"
 	"github.com/thejerf/suture"
@@ -74,7 +77,9 @@ func TestStopAfterBrokenConfig(t *testing.T) {
 	srv := newAPIService(protocol.LocalDeviceID, w, "../../test/h1/https-cert.pem", "../../test/h1/https-key.pem", "", nil, nil, nil, nil, nil, nil, nil, nil)
 	srv.started = make(chan string)

-	sup := suture.NewSimple("test")
+	sup := suture.New("test", suture.Spec{
+		PassThroughPanics: true,
+	})
 	sup.Add(srv)
 	sup.ServeBackground()

@@ -484,7 +489,9 @@ func startHTTP(cfg *mockedConfig) (string, error) {
 	svc.started = addrChan

 	// Actually start the API service
-	supervisor := suture.NewSimple("API test")
+	supervisor := suture.New("API test", suture.Spec{
+		PassThroughPanics: true,
+	})
 	supervisor.Add(svc)
 	supervisor.ServeBackground()

@@ -839,16 +846,24 @@ func TestAddressIsLocalhost(t *testing.T) {
 		// These are all valid localhost addresses
 		{"localhost", true},
 		{"LOCALHOST", true},
+		{"localhost.", true},
 		{"::1", true},
 		{"127.0.0.1", true},
+		{"127.23.45.56", true},
 		{"localhost:8080", true},
 		{"LOCALHOST:8000", true},
+		{"localhost.:8080", true},
 		{"[::1]:8080", true},
 		{"127.0.0.1:8080", true},
+		{"127.23.45.56:8080", true},

 		// These are all non-localhost addresses
 		{"example.com", false},
 		{"example.com:8080", false},
+		{"localhost.com", false},
+		{"localhost.com:8080", false},
+		{"www.localhost", false},
+		{"www.localhost:8080", false},
 		{"192.0.2.10", false},
 		{"192.0.2.10:8080", false},
 		{"0.0.0.0", false},
@@ -957,3 +972,87 @@ func TestEventMasks(t *testing.T) {
 		t.Errorf("should have returned a valid, non-default event sub")
 	}
 }
+
+func TestBrowse(t *testing.T) {
+	pathSep := string(os.PathSeparator)
+
+	tmpDir, err := ioutil.TempDir("", "syncthing")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	if err := os.Mkdir(filepath.Join(tmpDir, "dir"), 0755); err != nil {
+		t.Fatal(err)
+	}
+	if err := ioutil.WriteFile(filepath.Join(tmpDir, "file"), []byte("hello"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.Mkdir(filepath.Join(tmpDir, "MiXEDCase"), 0755); err != nil {
+		t.Fatal(err)
+	}
+
+	// We expect completion to return the full path to the completed
+	// directory, with an ending slash.
+	dirPath := filepath.Join(tmpDir, "dir") + pathSep
+	mixedCaseDirPath := filepath.Join(tmpDir, "MiXEDCase") + pathSep
+
+	cases := []struct {
+		current string
+		returns []string
+	}{
+		// The direcotory without slash is completed to one with slash.
+		{tmpDir, []string{tmpDir + pathSep}},
+		// With slash it's completed to its contents.
+		// Dirs are given pathSeps.
+		// Files are not returned.
+		{tmpDir + pathSep, []string{mixedCaseDirPath, dirPath}},
+		// Globbing is automatic based on prefix.
+		{tmpDir + pathSep + "d", []string{dirPath}},
+		{tmpDir + pathSep + "di", []string{dirPath}},
+		{tmpDir + pathSep + "dir", []string{dirPath}},
+		{tmpDir + pathSep + "f", nil},
+		{tmpDir + pathSep + "q", nil},
+		// Globbing is case-insensitve
+		{tmpDir + pathSep + "mixed", []string{mixedCaseDirPath}},
+	}
+
+	for _, tc := range cases {
+		ret := browseFiles(tc.current, fs.FilesystemTypeBasic)
+		if !equalStrings(ret, tc.returns) {
+			t.Errorf("browseFiles(%q) => %q, expected %q", tc.current, ret, tc.returns)
+		}
+	}
+}
+
+func TestPrefixMatch(t *testing.T) {
+	cases := []struct {
+		s        string
+		prefix   string
+		expected int
+	}{
+		{"aaaA", "aaa", matchExact},
+		{"AAAX", "BBB", noMatch},
+		{"AAAX", "aAa", matchCaseIns},
+		{"äÜX", "äü", matchCaseIns},
+	}
+
+	for _, tc := range cases {
+		ret := checkPrefixMatch(tc.s, tc.prefix)
+		if ret != tc.expected {
+			t.Errorf("checkPrefixMatch(%q, %q) => %v, expected %v", tc.s, tc.prefix, ret, tc.expected)
+		}
+	}
+}
+
+func equalStrings(a, b []string) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}
--- a/cmd/syncthing/heapprof.go
+++ b/cmd/syncthing/heapprof.go
@@ -49,7 +49,7 @@ func saveHeapProfiles(rate int) {
 				panic(err)
 			}

-			_ = os.Remove(name) // Error deliberately ignored
+			os.Remove(name) // Error deliberately ignored
 			err = os.Rename(name+".tmp", name)
 			if err != nil {
 				panic(err)
--- a/cmd/syncthing/locations.go
+++ b/cmd/syncthing/locations.go
@@ -1,125 +0,0 @@
-// Copyright (C) 2015 The Syncthing Authors.
-//
-// This Source Code Form is subject to the terms of the Mozilla Public
-// License, v. 2.0. If a copy of the MPL was not distributed with this file,
-// You can obtain one at https://mozilla.org/MPL/2.0/.
-
-package main
-
-import (
-	"os"
-	"path/filepath"
-	"runtime"
-	"strings"
-	"time"
-
-	"github.com/syncthing/syncthing/lib/osutil"
-)
-
-type locationEnum string
-
-// Use strings as keys to make printout and serialization of the locations map
-// more meaningful.
-const (
-	locConfigFile    locationEnum = "config"
-	locCertFile                   = "certFile"
-	locKeyFile                    = "keyFile"
-	locHTTPSCertFile              = "httpsCertFile"
-	locHTTPSKeyFile               = "httpsKeyFile"
-	locDatabase                   = "database"
-	locLogFile                    = "logFile"
-	locCsrfTokens                 = "csrfTokens"
-	locPanicLog                   = "panicLog"
-	locAuditLog                   = "auditLog"
-	locGUIAssets                  = "GUIAssets"
-	locDefFolder                  = "defFolder"
-)
-
-// Platform dependent directories
-var baseDirs = map[string]string{
-	"config": defaultConfigDir(), // Overridden by -home flag
-	"home":   homeDir(),          // User's home directory, *not* -home flag
-}
-
-// Use the variables from baseDirs here
-var locations = map[locationEnum]string{
-	locConfigFile:    "${config}/config.xml",
-	locCertFile:      "${config}/cert.pem",
-	locKeyFile:       "${config}/key.pem",
-	locHTTPSCertFile: "${config}/https-cert.pem",
-	locHTTPSKeyFile:  "${config}/https-key.pem",
-	locDatabase:      "${config}/index-v0.14.0.db",
-	locLogFile:       "${config}/syncthing.log", // -logfile on Windows
-	locCsrfTokens:    "${config}/csrftokens.txt",
-	locPanicLog:      "${config}/panic-${timestamp}.log",
-	locAuditLog:      "${config}/audit-${timestamp}.log",
-	locGUIAssets:     "${config}/gui",
-	locDefFolder:     "${home}/Sync",
-}
-
-// expandLocations replaces the variables in the location map with actual
-// directory locations.
-func expandLocations() error {
-	for key, dir := range locations {
-		for varName, value := range baseDirs {
-			dir = strings.Replace(dir, "${"+varName+"}", value, -1)
-		}
-		var err error
-		dir, err = osutil.ExpandTilde(dir)
-		if err != nil {
-			return err
-		}
-		locations[key] = dir
-	}
-	return nil
-}
-
-// defaultConfigDir returns the default configuration directory, as figured
-// out by various the environment variables present on each platform, or dies
-// trying.
-func defaultConfigDir() string {
-	switch runtime.GOOS {
-	case "windows":
-		if p := os.Getenv("LocalAppData"); p != "" {
-			return filepath.Join(p, "Syncthing")
-		}
-		return filepath.Join(os.Getenv("AppData"), "Syncthing")
-
-	case "darwin":
-		dir, err := osutil.ExpandTilde("~/Library/Application Support/Syncthing")
-		if err != nil {
-			l.Fatalln(err)
-		}
-		return dir
-
-	default:
-		if xdgCfg := os.Getenv("XDG_CONFIG_HOME"); xdgCfg != "" {
-			return filepath.Join(xdgCfg, "syncthing")
-		}
-		dir, err := osutil.ExpandTilde("~/.config/syncthing")
-		if err != nil {
-			l.Fatalln(err)
-		}
-		return dir
-	}
-}
-
-// homeDir returns the user's home directory, or dies trying.
-func homeDir() string {
-	home, err := osutil.ExpandTilde("~")
-	if err != nil {
-		l.Fatalln(err)
-	}
-	return home
-}
-
-func timestampedLoc(key locationEnum) string {
-	// We take the roundtrip via "${timestamp}" instead of passing the path
-	// directly through time.Format() to avoid issues when the path we are
-	// expanding contains numbers; otherwise for example
-	// /home/user2006/.../panic-20060102-150405.log would get both instances of
-	// 2006 replaced by 2015...
-	tpl := locations[key]
-	now := time.Now().Format("20060102-150405")
-	return strings.Replace(tpl, "${timestamp}", now, -1)
-}
--- a/cmd/syncthing/main.go
+++ b/cmd/syncthing/main.go
@@ -15,14 +15,13 @@ import (
 	"io"
 	"io/ioutil"
 	"log"
-	"net"
 	"net/http"
+	_ "net/http/pprof" // Need to import this to support STPROFILER.
 	"net/url"
 	"os"
 	"os/signal"
 	"path"
 	"path/filepath"
-	"regexp"
 	"runtime"
 	"runtime/pprof"
 	"sort"
@@ -31,12 +30,15 @@ import (
 	"syscall"
 	"time"

+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/connections"
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/dialer"
 	"github.com/syncthing/syncthing/lib/discover"
 	"github.com/syncthing/syncthing/lib/events"
+	"github.com/syncthing/syncthing/lib/fs"
+	"github.com/syncthing/syncthing/lib/locations"
 	"github.com/syncthing/syncthing/lib/logger"
 	"github.com/syncthing/syncthing/lib/model"
 	"github.com/syncthing/syncthing/lib/osutil"
@@ -45,26 +47,8 @@ import (
 	"github.com/syncthing/syncthing/lib/sha256"
 	"github.com/syncthing/syncthing/lib/tlsutil"
 	"github.com/syncthing/syncthing/lib/upgrade"
-	"github.com/syncthing/syncthing/lib/weakhash"

 	"github.com/thejerf/suture"
-
-	_ "net/http/pprof" // Need to import this to support STPROFILER.
-)
-
-var (
-	Version           = "unknown-dev"
-	Codename          = "Dysprosium Dragonfly"
-	BuildStamp        = "0"
-	BuildDate         time.Time
-	BuildHost         = "unknown"
-	BuildUser         = "unknown"
-	IsRelease         bool
-	IsCandidate       bool
-	IsBeta            bool
-	LongVersion       string
-	BuildTags         []string
-	allowedVersionExp = regexp.MustCompile(`^v\d+\.\d+\.\d+(-[a-z0-9]+)*(\.\d+)*(\+\d+-g[0-9a-f]+)?(-[^\s]+)?$`)
 )

 const (
@@ -78,65 +62,15 @@ const (
 const (
 	bepProtocolName      = "bep/1.0"
 	tlsDefaultCommonName = "syncthing"
-	httpsRSABits         = 2048
-	bepRSABits           = 0 // 384 bit ECDSA used instead
 	defaultEventTimeout  = time.Minute
 	maxSystemErrors      = 5
 	initialSystemLog     = 10
 	maxSystemLog         = 250
 )

-// The discovery results are sorted by their source priority.
-const (
-	ipv6LocalDiscoveryPriority = iota
-	ipv4LocalDiscoveryPriority
-	globalDiscoveryPriority
-)
-
-func init() {
-	if Version != "unknown-dev" {
-		// If not a generic dev build, version string should come from git describe
-		if !allowedVersionExp.MatchString(Version) {
-			l.Fatalf("Invalid version string %q;\n\tdoes not match regexp %v", Version, allowedVersionExp)
-		}
-	}
-}
-
-func setBuildMetadata() {
-	// Check for a clean release build. A release is something like
-	// "v0.1.2", with an optional suffix of letters and dot separated
-	// numbers like "-beta3.47". If there's more stuff, like a plus sign and
-	// a commit hash and so on, then it's not a release. If it has a dash in
-	// it, it's some sort of beta, release candidate or special build. If it
-	// has "-rc." in it, like "v0.14.35-rc.42", then it's a candidate build.
-	//
-	// So, every build that is not a stable release build has IsBeta = true.
-	// This is used to enable some extra debugging (the deadlock detector).
-	//
-	// Release candidate builds are also "betas" from this point of view and
-	// will have that debugging enabled. In addition, some features are
-	// forced for release candidates - auto upgrade, and usage reporting.
-
-	exp := regexp.MustCompile(`^v\d+\.\d+\.\d+(-[a-z]+[\d\.]+)?$`)
-	IsRelease = exp.MatchString(Version)
-	IsCandidate = strings.Contains(Version, "-rc.")
-	IsBeta = strings.Contains(Version, "-")
-
-	stamp, _ := strconv.Atoi(BuildStamp)
-	BuildDate = time.Unix(int64(stamp), 0)
-
-	date := BuildDate.UTC().Format("2006-01-02 15:04:05 MST")
-	LongVersion = fmt.Sprintf(`syncthing %s "%s" (%s %s-%s) %s@%s %s`, Version, Codename, runtime.Version(), runtime.GOOS, runtime.GOARCH, BuildUser, BuildHost, date)
-
-	if len(BuildTags) > 0 {
-		LongVersion = fmt.Sprintf("%s [%s]", LongVersion, strings.Join(BuildTags, ", "))
-	}
-}
-
 var (
 	myID protocol.DeviceID
 	stop = make(chan int)
-	lans []*net.IPNet
 )

 const (
@@ -185,14 +119,11 @@ are mostly useful for developers. Use with care.
 STPERFSTATS       Write running performance statistics to perf-$pid.csv. Not
                   supported on Windows.

- STDEADLOCK        Used for debugging internal deadlocks. Use only under
-                   direction of a developer.
-
 STDEADLOCKTIMEOUT Used for debugging internal deadlocks; sets debug
                   sensitivity. Use only under direction of a developer.

- STDEADLOCKTHRESHOLD Used for debugging internal deadlocks; sets debug
-                     sensitivity.  Use only under direction of a developer.
+ STLOCKTHRESHOLD   Used for debugging internal deadlocks; sets debug
+                   sensitivity.  Use only under direction of a developer.

 STNORESTART       Equivalent to the -no-restart argument. Disable the
                   Syncthing monitor process which handles restarts for some
@@ -206,6 +137,11 @@ are mostly useful for developers. Use with care.
                   "minio" for the github.com/minio/sha256-simd implementation,
                   and blank (the default) for auto detection.

+ STRECHECKDBEVERY  Set to a time interval to override the default database
+                   check interval of 30 days (720h). The interval understands
+                   "h", "m" and "s" abbreviations for hours minutes and seconds.
+                   Valid values are like "720h", "30s", etc.
+
 GOMAXPROCS        Set the maximum number of CPU cores to use. Defaults to all
                   available CPU cores.

@@ -235,6 +171,7 @@ type RuntimeOptions struct {
 	resetDeltaIdxs bool
 	showVersion    bool
 	showPaths      bool
+	showDeviceId   bool
 	doUpgrade      bool
 	doUpgradeCheck bool
 	upgradeTo      string
@@ -256,6 +193,7 @@ type RuntimeOptions struct {
 	cpuProfile     bool
 	stRestarting   bool
 	logFlags       int
+	showHelp       bool
 }

 func defaultRuntimeOptions() RuntimeOptions {
@@ -299,13 +237,15 @@ func parseCommandLineOptions() RuntimeOptions {
 	flag.BoolVar(&options.doUpgrade, "upgrade", false, "Perform upgrade")
 	flag.BoolVar(&options.doUpgradeCheck, "upgrade-check", false, "Check for available upgrade")
 	flag.BoolVar(&options.showVersion, "version", false, "Show version")
+	flag.BoolVar(&options.showHelp, "help", false, "Show this help")
 	flag.BoolVar(&options.showPaths, "paths", false, "Show configuration paths")
+	flag.BoolVar(&options.showDeviceId, "device-id", false, "Show the device ID")
 	flag.StringVar(&options.upgradeTo, "upgrade-to", options.upgradeTo, "Force upgrade directly from specified URL")
 	flag.BoolVar(&options.auditEnabled, "audit", false, "Write events to audit file")
 	flag.BoolVar(&options.verbose, "verbose", false, "Print verbose log output")
 	flag.BoolVar(&options.paused, "paused", false, "Start with all devices and folders paused")
 	flag.BoolVar(&options.unpaused, "unpaused", false, "Start with all devices and folders unpaused")
-	flag.StringVar(&options.logFile, "logfile", options.logFile, "Log file name (use \"-\" for stdout)")
+	flag.StringVar(&options.logFile, "logfile", options.logFile, "Log file name (still always logs to stdout). Cannot be used together with -no-restart/STNORESTART environment variable.")
 	flag.StringVar(&options.auditFile, "auditfile", options.auditFile, "Specify audit file (use \"-\" for stdout, \"--\" for stderr)")
 	if runtime.GOOS == "windows" {
 		// Allow user to hide the console window
@@ -325,8 +265,6 @@ func parseCommandLineOptions() RuntimeOptions {
 }

 func main() {
-	setBuildMetadata()
-
 	options := parseCommandLineOptions()
 	l.SetFlags(options.logFlags)

@@ -360,32 +298,49 @@ func main() {
 				l.Fatalln(err)
 			}
 		}
-		baseDirs["config"] = options.confDir
-	}
-
-	if err := expandLocations(); err != nil {
-		l.Fatalln(err)
+		if err := locations.SetBaseDir(locations.ConfigBaseDir, options.confDir); err != nil {
+			l.Fatalln(err)
+		}
 	}

 	if options.logFile == "" {
 		// Blank means use the default logfile location. We must set this
 		// *after* expandLocations above.
-		options.logFile = locations[locLogFile]
+		options.logFile = locations.Get(locations.LogFile)
 	}

 	if options.assetDir == "" {
 		// The asset dir is blank if STGUIASSETS wasn't set, in which case we
 		// should look for extra assets in the default place.
-		options.assetDir = locations[locGUIAssets]
+		options.assetDir = locations.Get(locations.GUIAssets)
 	}

 	if options.showVersion {
-		fmt.Println(LongVersion)
+		fmt.Println(build.LongVersion)
+		return
+	}
+
+	if options.showHelp {
+		flag.Usage()
 		return
 	}

 	if options.showPaths {
-		showPaths()
+		showPaths(options)
+		return
+	}
+
+	if options.showDeviceId {
+		cert, err := tls.LoadX509KeyPair(
+			locations.Get(locations.CertFile),
+			locations.Get(locations.KeyFile),
+		)
+		if err != nil {
+			l.Fatalln("Error reading device ID:", err)
+		}
+
+		myID = protocol.NewDeviceID(cert.Certificate[0])
+		fmt.Println(myID)
 		return
 	}

@@ -400,7 +355,7 @@ func main() {
 	}

 	// Ensure that our home directory exists.
-	ensureDir(baseDirs["config"], 0700)
+	ensureDir(locations.GetBaseDir(locations.ConfigBaseDir), 0700)

 	if options.upgradeTo != "" {
 		err := upgrade.ToURL(options.upgradeTo)
@@ -423,7 +378,9 @@ func main() {
 	}

 	if options.resetDatabase {
-		resetDB()
+		if err := resetDB(); err != nil {
+			l.Fatalln("Resetting database:", err)
+		}
 		return
 	}

@@ -435,16 +392,18 @@ func main() {
 }

 func openGUI() {
-	cfg, _ := loadConfig()
+	cfg, _ := loadOrDefaultConfig()
 	if cfg.GUI().Enabled {
-		openURL(cfg.GUI().URL())
+		if err := openURL(cfg.GUI().URL()); err != nil {
+			l.Fatalln("Open URL:", err)
+		}
 	} else {
 		l.Warnln("Browser: GUI is currently disabled")
 	}
 }

 func generate(generateDir string) {
-	dir, err := osutil.ExpandTilde(generateDir)
+	dir, err := fs.ExpandTilde(generateDir)
 	if err != nil {
 		l.Fatalln("generate:", err)
 	}
@@ -456,7 +415,7 @@ func generate(generateDir string) {
 		l.Warnln("Key exists; will not overwrite.")
 		l.Infoln("Device ID:", protocol.NewDeviceID(cert.Certificate[0]))
 	} else {
-		cert, err = tlsutil.NewCertificate(certFile, keyFile, tlsDefaultCommonName, bepRSABits)
+		cert, err = tlsutil.NewCertificate(certFile, keyFile, tlsDefaultCommonName)
 		if err != nil {
 			l.Fatalln("Create certificate:", err)
 		}
@@ -474,9 +433,7 @@ func generate(generateDir string) {
 		l.Warnln("Config exists; will not overwrite.")
 		return
 	}
-	var myName, _ = os.Hostname()
-	var newCfg = defaultConfig(myName)
-	var cfg = config.Wrap(cfgFile, newCfg)
+	var cfg = defaultConfig(cfgFile)
 	err = cfg.Save()
 	if err != nil {
 		l.Warnln("Failed to save config", err)
@@ -506,26 +463,26 @@ func debugFacilities() string {
 }

 func checkUpgrade() upgrade.Release {
-	cfg, _ := loadConfig()
+	cfg, _ := loadOrDefaultConfig()
 	opts := cfg.Options()
-	release, err := upgrade.LatestRelease(opts.ReleasesURL, Version, opts.UpgradeToPreReleases)
+	release, err := upgrade.LatestRelease(opts.ReleasesURL, build.Version, opts.UpgradeToPreReleases)
 	if err != nil {
 		l.Fatalln("Upgrade:", err)
 	}

-	if upgrade.CompareVersions(release.Tag, Version) <= 0 {
+	if upgrade.CompareVersions(release.Tag, build.Version) <= 0 {
 		noUpgradeMessage := "No upgrade available (current %q >= latest %q)."
-		l.Infof(noUpgradeMessage, Version, release.Tag)
+		l.Infof(noUpgradeMessage, build.Version, release.Tag)
 		os.Exit(exitNoUpgradeAvailable)
 	}

-	l.Infof("Upgrade available (current %q < latest %q)", Version, release.Tag)
+	l.Infof("Upgrade available (current %q < latest %q)", build.Version, release.Tag)
 	return release
 }

 func performUpgrade(release upgrade.Release) {
 	// Use leveldb database locks to protect against concurrent upgrades
-	_, err := db.Open(locations[locDatabase])
+	_, err := db.Open(locations.Get(locations.Database))
 	if err == nil {
 		err = upgrade.To(release)
 		if err != nil {
@@ -544,7 +501,7 @@ func performUpgrade(release upgrade.Release) {
 }

 func upgradeViaRest() error {
-	cfg, _ := loadConfig()
+	cfg, _ := loadOrDefaultConfig()
 	u, err := url.Parse(cfg.GUI().URL())
 	if err != nil {
 		return err
@@ -588,6 +545,7 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 		Log: func(line string) {
 			l.Debugln(line)
 		},
+		PassThroughPanics: true,
 	})
 	mainService.ServeBackground()

@@ -622,10 +580,17 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 	osutil.MaximizeOpenFileLimit()

 	// Ensure that we have a certificate and key.
-	cert, err := tls.LoadX509KeyPair(locations[locCertFile], locations[locKeyFile])
+	cert, err := tls.LoadX509KeyPair(
+		locations.Get(locations.CertFile),
+		locations.Get(locations.KeyFile),
+	)
 	if err != nil {
 		l.Infof("Generating ECDSA key and certificate for %s...", tlsDefaultCommonName)
-		cert, err = tlsutil.NewCertificate(locations[locCertFile], locations[locKeyFile], tlsDefaultCommonName, bepRSABits)
+		cert, err = tlsutil.NewCertificate(
+			locations.Get(locations.CertFile),
+			locations.Get(locations.KeyFile),
+			tlsDefaultCommonName,
+		)
 		if err != nil {
 			l.Fatalln(err)
 		}
@@ -634,24 +599,22 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 	myID = protocol.NewDeviceID(cert.Certificate[0])
 	l.SetPrefix(fmt.Sprintf("[%s] ", myID.String()[:5]))

-	l.Infoln(LongVersion)
+	l.Infoln(build.LongVersion)
 	l.Infoln("My ID:", myID)

+	// Select SHA256 implementation and report. Affected by the
+	// STHASHING environment variable.
 	sha256.SelectAlgo()
 	sha256.Report()
-	perfWithWeakHash := cpuBench(3, 150*time.Millisecond, true)
-	l.Infof("Hashing performance with weak hash is %.02f MB/s", perfWithWeakHash)
-	perfWithoutWeakHash := cpuBench(3, 150*time.Millisecond, false)
-	l.Infof("Hashing performance without weak hash is %.02f MB/s", perfWithoutWeakHash)

 	// Emit the Starting event, now that we know who we are.

 	events.Default.Log(events.Starting, map[string]string{
-		"home": baseDirs["config"],
+		"home": locations.GetBaseDir(locations.ConfigBaseDir),
 		"myID": myID.String(),
 	})

-	cfg := loadOrCreateConfig()
+	cfg := loadConfigAtStartup()

 	if err := checkShortIDs(cfg); err != nil {
 		l.Fatalln("Short device IDs are in conflict. Unlucky!\n  Regenerate the device ID of one of the following:\n  ", err)
@@ -668,83 +631,28 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 		}()
 	}

-	// The TLS configuration is used for both the listening socket and outgoing
-	// connections.
+	perf := cpuBench(3, 150*time.Millisecond, true)
+	l.Infof("Hashing performance is %.02f MB/s", perf)

-	tlsCfg := &tls.Config{
-		Certificates:           []tls.Certificate{cert},
-		NextProtos:             []string{bepProtocolName},
-		ClientAuth:             tls.RequestClientCert,
-		SessionTicketsDisabled: true,
-		InsecureSkipVerify:     true,
-		MinVersion:             tls.VersionTLS12,
-		CipherSuites: []uint16{
-			0xCCA8, // TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305, Go 1.8
-			0xCCA9, // TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305, Go 1.8
-			tls.TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,
-			tls.TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
-			tls.TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
-			tls.TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
-			tls.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
-			tls.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
-			tls.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
-			tls.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
-		},
-	}
-
-	opts := cfg.Options()
-
-	if opts.WeakHashSelectionMethod == config.WeakHashAuto {
-		if perfWithoutWeakHash*0.8 > perfWithWeakHash {
-			l.Infof("Weak hash disabled, as it has an unacceptable performance impact.")
-			weakhash.Enabled = false
-		} else {
-			l.Infof("Weak hash enabled, as it has an acceptable performance impact.")
-			weakhash.Enabled = true
-		}
-	} else if opts.WeakHashSelectionMethod == config.WeakHashNever {
-		l.Infof("Disabling weak hash")
-		weakhash.Enabled = false
-	} else if opts.WeakHashSelectionMethod == config.WeakHashAlways {
-		l.Infof("Enabling weak hash")
-		weakhash.Enabled = true
-	}
-
-	if (opts.MaxRecvKbps > 0 || opts.MaxSendKbps > 0) && !opts.LimitBandwidthInLan {
-		lans, _ = osutil.GetLans()
-		for _, lan := range opts.AlwaysLocalNets {
-			_, ipnet, err := net.ParseCIDR(lan)
-			if err != nil {
-				l.Infoln("Network", lan, "is malformed:", err)
-				continue
-			}
-			lans = append(lans, ipnet)
-		}
-
-		networks := make([]string, len(lans))
-		for i, lan := range lans {
-			networks[i] = lan.String()
-		}
-		l.Infoln("Local networks:", strings.Join(networks, ", "))
-	}
-
-	dbFile := locations[locDatabase]
+	dbFile := locations.Get(locations.Database)
 	ldb, err := db.Open(dbFile)
-
 	if err != nil {
-		l.Fatalln("Cannot open database:", err, "- Is another copy of Syncthing already running?")
+		l.Fatalln("Error opening database:", err)
+	}
+	if err := db.UpdateSchema(ldb); err != nil {
+		l.Fatalln("Database schema:", err)
 	}

 	if runtimeOptions.resetDeltaIdxs {
 		l.Infoln("Reinitializing delta index IDs")
-		ldb.DropDeltaIndexIDs()
+		db.DropDeltaIndexIDs(ldb)
 	}

 	protectedFiles := []string{
-		locations[locDatabase],
-		locations[locConfigFile],
-		locations[locCertFile],
-		locations[locKeyFile],
+		locations.Get(locations.Database),
+		locations.Get(locations.ConfigFile),
+		locations.Get(locations.CertFile),
+		locations.Get(locations.KeyFile),
 	}

 	// Remove database entries for folders that no longer exist in the config
@@ -756,25 +664,37 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 		}
 	}

-	if cfg.RawCopy().OriginalVersion == 15 {
-		// The config version 15->16 migration is about handling ignores and
-		// delta indexes and requires that we drop existing indexes that
-		// have been incorrectly ignore filtered.
-		ldb.DropDeltaIndexIDs()
-	}
-	if cfg.RawCopy().OriginalVersion < 19 {
-		// Converts old symlink types to new in the entire database.
-		ldb.ConvertSymlinkTypes()
-	}
+	// Grab the previously running version string from the database.

-	m := model.NewModel(cfg, myID, "syncthing", Version, ldb, protectedFiles)
+	miscDB := db.NewMiscDataNamespace(ldb)
+	prevVersion, _ := miscDB.String("prevVersion")

-	if t := os.Getenv("STDEADLOCKTIMEOUT"); len(t) > 0 {
-		it, err := strconv.Atoi(t)
-		if err == nil {
-			m.StartDeadlockDetector(time.Duration(it) * time.Second)
+	// Strip away prerelease/beta stuff and just compare the release
+	// numbers. 0.14.44 to 0.14.45-banana is an upgrade, 0.14.45-banana to
+	// 0.14.45-pineapple is not.
+
+	prevParts := strings.Split(prevVersion, "-")
+	curParts := strings.Split(build.Version, "-")
+	if prevParts[0] != curParts[0] {
+		if prevVersion != "" {
+			l.Infoln("Detected upgrade from", prevVersion, "to", build.Version)
 		}
-	} else if !IsRelease || IsBeta {
+
+		// Drop delta indexes in case we've changed random stuff we
+		// shouldn't have. We will resend our index on next connect.
+		db.DropDeltaIndexIDs(ldb)
+
+		// Remember the new version.
+		miscDB.PutString("prevVersion", build.Version)
+	}
+
+	m := model.NewModel(cfg, myID, "syncthing", build.Version, ldb, protectedFiles)
+
+	if t := os.Getenv("STDEADLOCKTIMEOUT"); t != "" {
+		if secs, _ := strconv.Atoi(t); secs > 0 {
+			m.StartDeadlockDetector(time.Duration(secs) * time.Second)
+		}
+	} else if !build.IsRelease || build.IsBeta {
 		m.StartDeadlockDetector(20 * time.Minute)
 	}

@@ -801,9 +721,19 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 	cachedDiscovery := discover.NewCachingMux()
 	mainService.Add(cachedDiscovery)

+	// The TLS configuration is used for both the listening socket and outgoing
+	// connections.
+
+	tlsCfg := tlsutil.SecureDefault()
+	tlsCfg.Certificates = []tls.Certificate{cert}
+	tlsCfg.NextProtos = []string{bepProtocolName}
+	tlsCfg.ClientAuth = tls.RequestClientCert
+	tlsCfg.SessionTicketsDisabled = true
+	tlsCfg.InsecureSkipVerify = true
+
 	// Start connection management

-	connectionsService := connections.NewService(cfg, myID, m, tlsCfg, cachedDiscovery, bepProtocolName, tlsDefaultCommonName, lans)
+	connectionsService := connections.NewService(cfg, myID, m, tlsCfg, cachedDiscovery, bepProtocolName, tlsDefaultCommonName)
 	mainService.Add(connectionsService)

 	if cfg.Options().GlobalAnnEnabled {
@@ -818,7 +748,7 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 			// Each global discovery server gets its results cached for five
 			// minutes, and is not asked again for a minute when it's returned
 			// unsuccessfully.
-			cachedDiscovery.Add(gd, 5*time.Minute, time.Minute, globalDiscoveryPriority)
+			cachedDiscovery.Add(gd, 5*time.Minute, time.Minute)
 		}
 	}

@@ -828,14 +758,14 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 		if err != nil {
 			l.Warnln("IPv4 local discovery:", err)
 		} else {
-			cachedDiscovery.Add(bcd, 0, 0, ipv4LocalDiscoveryPriority)
+			cachedDiscovery.Add(bcd, 0, 0)
 		}
 		// v6 multicasts
 		mcd, err := discover.NewLocal(myID, cfg.Options().LocalAnnMCAddr, connectionsService)
 		if err != nil {
 			l.Warnln("IPv6 local discovery:", err)
 		} else {
-			cachedDiscovery.Add(mcd, 0, 0, ipv6LocalDiscoveryPriority)
+			cachedDiscovery.Add(mcd, 0, 0)
 		}
 	}

@@ -846,45 +776,44 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 	if runtimeOptions.cpuProfile {
 		f, err := os.Create(fmt.Sprintf("cpu-%d.pprof", os.Getpid()))
 		if err != nil {
-			log.Fatal(err)
+			l.Fatalln("Creating profile:", err)
+		}
+		if err := pprof.StartCPUProfile(f); err != nil {
+			l.Fatalln("Starting profile:", err)
 		}
-		pprof.StartCPUProfile(f)
 	}

+	myDev, _ := cfg.Device(myID)
+	l.Infof(`My name is "%v"`, myDev.Name)
 	for _, device := range cfg.Devices() {
-		if len(device.Name) > 0 {
-			l.Infof("Device %s is %q at %v", device.DeviceID, device.Name, device.Addresses)
+		if device.DeviceID != myID {
+			l.Infof(`Device %s is "%v" at %v`, device.DeviceID, device.Name, device.Addresses)
 		}
 	}

 	// Candidate builds always run with usage reporting.

-	if IsCandidate {
+	if opts := cfg.Options(); build.IsCandidate {
 		l.Infoln("Anonymous usage reporting is always enabled for candidate releases.")
-		opts.URAccepted = usageReportVersion
-		// Unique ID will be set and config saved below if necessary.
+		if opts.URAccepted != usageReportVersion {
+			opts.URAccepted = usageReportVersion
+			cfg.SetOptions(opts)
+			cfg.Save()
+			// Unique ID will be set and config saved below if necessary.
+		}
 	}

-	if opts.URAccepted > 0 && opts.URAccepted < usageReportVersion {
-		l.Infoln("Anonymous usage report has changed; revoking acceptance")
-		opts.URAccepted = 0
-		opts.URUniqueID = ""
-		cfg.SetOptions(opts)
-	}
-
-	if opts.URAccepted >= usageReportVersion && opts.URUniqueID == "" {
-		// Generate and save a new unique ID if it is missing.
+	// If we are going to do usage reporting, ensure we have a valid unique ID.
+	if opts := cfg.Options(); opts.URAccepted > 0 && opts.URUniqueID == "" {
 		opts.URUniqueID = rand.String(8)
 		cfg.SetOptions(opts)
 		cfg.Save()
 	}

-	// The usageReportingManager registers itself to listen to configuration
-	// changes, and there's nothing more we need to tell it from the outside.
-	// Hence we don't keep the returned pointer.
-	newUsageReportingManager(cfg, m)
+	usageReportingSvc := newUsageReportingService(cfg, m, connectionsService)
+	mainService.Add(usageReportingSvc)

-	if opts.RestartOnWakeup {
+	if opts := cfg.Options(); opts.RestartOnWakeup {
 		go standbyMonitor()
 	}

@@ -892,9 +821,9 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 	// unless we are in a build where it's disabled or the STNOUPGRADE
 	// environment variable is set.

-	if IsCandidate && !upgrade.DisabledByCompilation && !noUpgradeFromEnv {
+	if build.IsCandidate && !upgrade.DisabledByCompilation && !noUpgradeFromEnv {
 		l.Infoln("Automatic upgrade is always enabled for candidate releases.")
-		if opts.AutoUpgradeIntervalH == 0 || opts.AutoUpgradeIntervalH > 24 {
+		if opts := cfg.Options(); opts.AutoUpgradeIntervalH == 0 || opts.AutoUpgradeIntervalH > 24 {
 			opts.AutoUpgradeIntervalH = 12
 			// Set the option into the config as well, as the auto upgrade
 			// loop expects to read a valid interval from there.
@@ -905,7 +834,7 @@ func syncthingMain(runtimeOptions RuntimeOptions) {
 		// not, as otherwise they cannot step off the candidate channel.
 	}

-	if opts.AutoUpgradeIntervalH > 0 {
+	if opts := cfg.Options(); opts.AutoUpgradeIntervalH > 0 {
 		if noUpgradeFromEnv {
 			l.Infof("No automatic upgrades; STNOUPGRADE environment variable defined.")
 		} else {
@@ -923,6 +852,12 @@ func syncthingMain(runtimeOptions RuntimeOptions) {

 	cleanConfigDirectory()

+	if cfg.Options().SetLowPriority {
+		if err := osutil.SetLowPriority(); err != nil {
+			l.Warnln("Failed to lower process priority:", err)
+		}
+	}
+
 	code := <-stop

 	mainService.Stop()
@@ -958,26 +893,28 @@ func setupSignalHandling() {
 	}()
 }

-func loadConfig() (*config.Wrapper, error) {
-	cfgFile := locations[locConfigFile]
+func loadOrDefaultConfig() (*config.Wrapper, error) {
+	cfgFile := locations.Get(locations.ConfigFile)
 	cfg, err := config.Load(cfgFile, myID)

 	if err != nil {
-		myName, _ := os.Hostname()
-		newCfg := defaultConfig(myName)
-		cfg = config.Wrap(cfgFile, newCfg)
+		cfg = defaultConfig(cfgFile)
 	}

 	return cfg, err
 }

-func loadOrCreateConfig() *config.Wrapper {
-	cfg, err := loadConfig()
+func loadConfigAtStartup() *config.Wrapper {
+	cfgFile := locations.Get(locations.ConfigFile)
+	cfg, err := config.Load(cfgFile, myID)
 	if os.IsNotExist(err) {
+		cfg = defaultConfig(cfgFile)
 		cfg.Save()
-		l.Infof("Defaults saved. Edit %s to taste or use the GUI\n", cfg.ConfigPath())
+		l.Infof("Default config saved. Edit %s to taste or use the GUI\n", cfg.ConfigPath())
+	} else if err == io.EOF {
+		l.Fatalln("Failed to load config: unexpected end of file. Truncated or empty configuration?")
 	} else if err != nil {
-		l.Fatalln("Config:", err)
+		l.Fatalln("Failed to load config:", err)
 	}

 	if cfg.RawCopy().OriginalVersion != config.CurrentVersion {
@@ -1032,7 +969,7 @@ func startAuditing(mainService *suture.Supervisor, auditFile string) {
 		auditDest = "stderr"
 	} else {
 		if auditFile == "" {
-			auditFile = timestampedLoc(locAuditLog)
+			auditFile = locations.GetTimestamped(locations.AuditLog)
 			auditFlags = os.O_WRONLY | os.O_CREATE | os.O_EXCL
 		} else {
 			auditFlags = os.O_WRONLY | os.O_CREATE | os.O_APPEND
@@ -1068,7 +1005,7 @@ func setupGUI(mainService *suture.Supervisor, cfg *config.Wrapper, m *model.Mode
 	cpu := newCPUService()
 	mainService.Add(cpu)

-	api := newAPIService(myID, cfg, locations[locHTTPSCertFile], locations[locHTTPSKeyFile], runtimeOptions.assetDir, m, defaultSub, diskSub, discoverer, connectionsService, errors, systemLog, cpu)
+	api := newAPIService(myID, cfg, locations.Get(locations.HTTPSCertFile), locations.Get(locations.HTTPSKeyFile), runtimeOptions.assetDir, m, defaultSub, diskSub, discoverer, connectionsService, errors, systemLog, cpu)
 	cfg.Subscribe(api)
 	mainService.Add(api)

@@ -1076,59 +1013,25 @@ func setupGUI(mainService *suture.Supervisor, cfg *config.Wrapper, m *model.Mode
 		// Can potentially block if the utility we are invoking doesn't
 		// fork, and just execs, hence keep it in its own routine.
 		<-api.startedOnce
-		go openURL(guiCfg.URL())
+		go func() { _ = openURL(guiCfg.URL()) }()
 	}
 }

-func defaultConfig(myName string) config.Configuration {
-	var defaultFolder config.FolderConfiguration
+func defaultConfig(cfgFile string) *config.Wrapper {
+	newCfg := config.NewWithFreePorts(myID)

-	if !noDefaultFolder {
-		l.Infoln("Default folder created and/or linked to new config")
-		defaultFolder = config.NewFolderConfiguration("default", locations[locDefFolder])
-		defaultFolder.Label = "Default Folder"
-		defaultFolder.RescanIntervalS = 60
-		defaultFolder.MinDiskFree = config.Size{Value: 1, Unit: "%"}
-		defaultFolder.Devices = []config.FolderDeviceConfiguration{{DeviceID: myID}}
-		defaultFolder.AutoNormalize = true
-		defaultFolder.MaxConflicts = -1
-	} else {
+	if noDefaultFolder {
 		l.Infoln("We will skip creation of a default folder on first start since the proper envvar is set")
+		return config.Wrap(cfgFile, newCfg)
 	}

-	thisDevice := config.NewDeviceConfiguration(myID, myName)
-	thisDevice.Addresses = []string{"dynamic"}
-
-	newCfg := config.New(myID)
-	if !noDefaultFolder {
-		newCfg.Folders = []config.FolderConfiguration{defaultFolder}
-	}
-	newCfg.Devices = []config.DeviceConfiguration{thisDevice}
-
-	port, err := getFreePort("127.0.0.1", 8384)
-	if err != nil {
-		l.Fatalln("get free port (GUI):", err)
-	}
-	newCfg.GUI.RawAddress = fmt.Sprintf("127.0.0.1:%d", port)
-
-	port, err = getFreePort("0.0.0.0", 22000)
-	if err != nil {
-		l.Fatalln("get free port (BEP):", err)
-	}
-	if port == 22000 {
-		newCfg.Options.ListenAddresses = []string{"default"}
-	} else {
-		newCfg.Options.ListenAddresses = []string{
-			fmt.Sprintf("tcp://%s", net.JoinHostPort("0.0.0.0", strconv.Itoa(port))),
-			"dynamic+https://relays.syncthing.net/endpoint",
-		}
-	}
-
-	return newCfg
+	newCfg.Folders = append(newCfg.Folders, config.NewFolderConfiguration(myID, "default", "Default Folder", fs.FilesystemTypeBasic, locations.Get(locations.DefFolder)))
+	l.Infoln("Default folder created and/or linked to new config")
+	return config.Wrap(cfgFile, newCfg)
 }

 func resetDB() error {
-	return os.RemoveAll(locations[locDatabase])
+	return os.RemoveAll(locations.Get(locations.Database))
 }

 func restart() {
@@ -1141,19 +1044,20 @@ func shutdown() {
 	stop <- exitSuccess
 }

-func ensureDir(dir string, mode os.FileMode) {
-	err := osutil.MkdirAll(dir, mode)
+func ensureDir(dir string, mode fs.FileMode) {
+	fs := fs.NewFilesystem(fs.FilesystemTypeBasic, dir)
+	err := fs.MkdirAll(".", mode)
 	if err != nil {
 		l.Fatalln(err)
 	}

-	if fi, err := os.Stat(dir); err == nil {
+	if fi, err := fs.Stat("."); err == nil {
 		// Apprently the stat may fail even though the mkdirall passed. If it
 		// does, we'll just assume things are in order and let other things
 		// fail (like loading or creating the config...).
 		currentMode := fi.Mode() & 0777
 		if currentMode != mode {
-			err := os.Chmod(dir, mode)
+			err := fs.Chmod(".", mode)
 			// This can fail on crappy filesystems, nothing we can do about it.
 			if err != nil {
 				l.Warnln(err)
@@ -1162,27 +1066,6 @@ func ensureDir(dir string, mode os.FileMode) {
 	}
 }

-// getFreePort returns a free TCP port fort listening on. The ports given are
-// tried in succession and the first to succeed is returned. If none succeed,
-// a random high port is returned.
-func getFreePort(host string, ports ...int) (int, error) {
-	for _, port := range ports {
-		c, err := net.Listen("tcp", fmt.Sprintf("%s:%d", host, port))
-		if err == nil {
-			c.Close()
-			return port, nil
-		}
-	}
-
-	c, err := net.Listen("tcp", host+":0")
-	if err != nil {
-		return 0, err
-	}
-	addr := c.Addr().(*net.TCPAddr)
-	c.Close()
-	return addr.Port, nil
-}
-
 func standbyMonitor() {
 	restartDelay := 60 * time.Second
 	now := time.Now()
@@ -1210,10 +1093,10 @@ func autoUpgrade(cfg *config.Wrapper) {
 		select {
 		case event := <-sub.C():
 			data, ok := event.Data.(map[string]string)
-			if !ok || data["clientName"] != "syncthing" || upgrade.CompareVersions(data["clientVersion"], Version) != upgrade.Newer {
+			if !ok || data["clientName"] != "syncthing" || upgrade.CompareVersions(data["clientVersion"], build.Version) != upgrade.Newer {
 				continue
 			}
-			l.Infof("Connected to device %s with a newer version (current %q < remote %q). Checking for upgrades.", data["id"], Version, data["clientVersion"])
+			l.Infof("Connected to device %s with a newer version (current %q < remote %q). Checking for upgrades.", data["id"], build.Version, data["clientVersion"])
 		case <-timer.C:
 		}

@@ -1225,7 +1108,7 @@ func autoUpgrade(cfg *config.Wrapper) {
 			checkInterval = time.Hour
 		}

-		rel, err := upgrade.LatestRelease(opts.ReleasesURL, Version, opts.UpgradeToPreReleases)
+		rel, err := upgrade.LatestRelease(opts.ReleasesURL, build.Version, opts.UpgradeToPreReleases)
 		if err == upgrade.ErrUpgradeUnsupported {
 			events.Default.Unsubscribe(sub)
 			return
@@ -1238,13 +1121,13 @@ func autoUpgrade(cfg *config.Wrapper) {
 			continue
 		}

-		if upgrade.CompareVersions(rel.Tag, Version) != upgrade.Newer {
+		if upgrade.CompareVersions(rel.Tag, build.Version) != upgrade.Newer {
 			// Skip equal, older or majorly newer (incompatible) versions
 			timer.Reset(checkInterval)
 			continue
 		}

-		l.Infof("Automatic upgrade (current %q < latest %q)", Version, rel.Tag)
+		l.Infof("Automatic upgrade (current %q < latest %q)", build.Version, rel.Tag)
 		err = upgrade.To(rel)
 		if err != nil {
 			l.Warnln("Automatic upgrade:", err)
@@ -1273,25 +1156,26 @@ func cleanConfigDirectory() {
 		"*.idx.gz":           30 * 24 * time.Hour, // these should for sure no longer exist
 		"backup-of-v0.8":     30 * 24 * time.Hour, // these neither
 		"tmp-index-sorter.*": time.Minute,         // these should never exist on startup
+		"support-bundle-*":   30 * 24 * time.Hour, // keep old support bundle zip or folder for a month
 	}

 	for pat, dur := range patterns {
-		pat = filepath.Join(baseDirs["config"], pat)
-		files, err := osutil.Glob(pat)
+		fs := fs.NewFilesystem(fs.FilesystemTypeBasic, locations.GetBaseDir(locations.ConfigBaseDir))
+		files, err := fs.Glob(pat)
 		if err != nil {
 			l.Infoln("Cleaning:", err)
 			continue
 		}

 		for _, file := range files {
-			info, err := osutil.Lstat(file)
+			info, err := fs.Lstat(file)
 			if err != nil {
 				l.Infoln("Cleaning:", err)
 				continue
 			}

 			if time.Since(info.ModTime()) > dur {
-				if err = os.RemoveAll(file); err != nil {
+				if err = fs.RemoveAll(file); err != nil {
 					l.Infoln("Cleaning:", err)
 				} else {
 					l.Infoln("Cleaned away old file", filepath.Base(file))
@@ -1316,14 +1200,14 @@ func checkShortIDs(cfg *config.Wrapper) error {
 	return nil
 }

-func showPaths() {
-	fmt.Printf("Configuration file:\n\t%s\n\n", locations[locConfigFile])
-	fmt.Printf("Database directory:\n\t%s\n\n", locations[locDatabase])
-	fmt.Printf("Device private key & certificate files:\n\t%s\n\t%s\n\n", locations[locKeyFile], locations[locCertFile])
-	fmt.Printf("HTTPS private key & certificate files:\n\t%s\n\t%s\n\n", locations[locHTTPSKeyFile], locations[locHTTPSCertFile])
-	fmt.Printf("Log file:\n\t%s\n\n", locations[locLogFile])
-	fmt.Printf("GUI override directory:\n\t%s\n\n", locations[locGUIAssets])
-	fmt.Printf("Default sync folder directory:\n\t%s\n\n", locations[locDefFolder])
+func showPaths(options RuntimeOptions) {
+	fmt.Printf("Configuration file:\n\t%s\n\n", locations.Get(locations.ConfigFile))
+	fmt.Printf("Database directory:\n\t%s\n\n", locations.Get(locations.Database))
+	fmt.Printf("Device private key & certificate files:\n\t%s\n\t%s\n\n", locations.Get(locations.KeyFile), locations.Get(locations.CertFile))
+	fmt.Printf("HTTPS private key & certificate files:\n\t%s\n\t%s\n\n", locations.Get(locations.HTTPSKeyFile), locations.Get(locations.HTTPSCertFile))
+	fmt.Printf("Log file:\n\t%s\n\n", options.logFile)
+	fmt.Printf("GUI override directory:\n\t%s\n\n", options.assetDir)
+	fmt.Printf("Default sync folder directory:\n\t%s\n\n", locations.Get(locations.DefFolder))
 }

 func setPauseState(cfg *config.Wrapper, paused bool) {
@@ -1334,7 +1218,7 @@ func setPauseState(cfg *config.Wrapper, paused bool) {
 	for i := range raw.Folders {
 		raw.Folders[i].Paused = paused
 	}
-	if err := cfg.Replace(raw); err != nil {
+	if _, err := cfg.Replace(raw); err != nil {
 		l.Fatalln("Cannot adjust paused state:", err)
 	}
 }
--- a/cmd/syncthing/main_test.go
+++ b/cmd/syncthing/main_test.go
@@ -36,29 +36,3 @@ func TestShortIDCheck(t *testing.T) {
 		t.Error("Should have gotten an error")
 	}
 }
-
-func TestAllowedVersions(t *testing.T) {
-	testcases := []struct {
-		ver     string
-		allowed bool
-	}{
-		{"v0.13.0", true},
-		{"v0.12.11+22-gabcdef0", true},
-		{"v0.13.0-beta0", true},
-		{"v0.13.0-beta47", true},
-		{"v0.13.0-beta47+1-gabcdef0", true},
-		{"v0.13.0-beta.0", true},
-		{"v0.13.0-beta.47", true},
-		{"v0.13.0-beta.0+1-gabcdef0", true},
-		{"v0.13.0-beta.47+1-gabcdef0", true},
-		{"v0.13.0-some-weird-but-allowed-tag", true},
-		{"v0.13.0-allowed.to.do.this", true},
-		{"v0.13.0+not.allowed.to.do.this", false},
-	}
-
-	for i, c := range testcases {
-		if allowed := allowedVersionExp.MatchString(c.ver); allowed != c.allowed {
-			t.Errorf("%d: incorrect result %v != %v for %q", i, allowed, c.allowed, c.ver)
-		}
-	}
-}
--- a/cmd/syncthing/mocked_config_test.go
+++ b/cmd/syncthing/mocked_config_test.go
@@ -24,6 +24,10 @@ func (c *mockedConfig) ListenAddresses() []string {
 	return nil
 }

+func (c *mockedConfig) LDAP() config.LDAPConfiguration {
+	return config.LDAPConfiguration{}
+}
+
 func (c *mockedConfig) RawCopy() config.Configuration {
 	cfg := config.Configuration{}
 	util.SetDefaults(&cfg.Options)
@@ -34,8 +38,8 @@ func (c *mockedConfig) Options() config.OptionsConfiguration {
 	return config.OptionsConfiguration{}
 }

-func (c *mockedConfig) Replace(cfg config.Configuration) error {
-	return nil
+func (c *mockedConfig) Replace(cfg config.Configuration) (config.Waiter, error) {
+	return noopWaiter{}, nil
 }

 func (c *mockedConfig) Subscribe(cm config.Committer) {}
@@ -48,12 +52,12 @@ func (c *mockedConfig) Devices() map[protocol.DeviceID]config.DeviceConfiguratio
 	return nil
 }

-func (c *mockedConfig) SetDevice(config.DeviceConfiguration) error {
-	return nil
+func (c *mockedConfig) SetDevice(config.DeviceConfiguration) (config.Waiter, error) {
+	return noopWaiter{}, nil
 }

-func (c *mockedConfig) SetDevices([]config.DeviceConfiguration) error {
-	return nil
+func (c *mockedConfig) SetDevices([]config.DeviceConfiguration) (config.Waiter, error) {
+	return noopWaiter{}, nil
 }

 func (c *mockedConfig) Save() error {
@@ -63,3 +67,7 @@ func (c *mockedConfig) Save() error {
 func (c *mockedConfig) RequiresRestart() bool {
 	return false
 }
+
+type noopWaiter struct{}
+
+func (noopWaiter) Wait() {}
--- a/cmd/syncthing/mocked_connections_test.go
+++ b/cmd/syncthing/mocked_connections_test.go
@@ -11,3 +11,7 @@ type mockedConnections struct{}
 func (m *mockedConnections) Status() map[string]interface{} {
 	return nil
 }
+
+func (m *mockedConnections) NATType() string {
+	return ""
+}
--- a/cmd/syncthing/mocked_discovery_test.go
+++ b/cmd/syncthing/mocked_discovery_test.go
@@ -44,7 +44,7 @@ func (m *mockedCachingMux) Cache() map[protocol.DeviceID]discover.CacheEntry {

 // from events.CachingMux

-func (m *mockedCachingMux) Add(finder discover.Finder, cacheTime, negCacheTime time.Duration, priority int) {
+func (m *mockedCachingMux) Add(finder discover.Finder, cacheTime, negCacheTime time.Duration) {
 }

 func (m *mockedCachingMux) ChildErrors() map[string]error {
--- a/cmd/syncthing/mocked_model_test.go
+++ b/cmd/syncthing/mocked_model_test.go
@@ -9,10 +9,12 @@ package main
 import (
 	"time"

+	"github.com/syncthing/syncthing/lib/connections"
 	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/model"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/stats"
+	"github.com/syncthing/syncthing/lib/versioner"
 )

 type mockedModel struct{}
@@ -27,8 +29,14 @@ func (m *mockedModel) Completion(device protocol.DeviceID, folder string) model.

 func (m *mockedModel) Override(folder string) {}

-func (m *mockedModel) NeedFolderFiles(folder string, page, perpage int) ([]db.FileInfoTruncated, []db.FileInfoTruncated, []db.FileInfoTruncated, int) {
-	return nil, nil, nil, 0
+func (m *mockedModel) Revert(folder string) {}
+
+func (m *mockedModel) NeedFolderFiles(folder string, page, perpage int) ([]db.FileInfoTruncated, []db.FileInfoTruncated, []db.FileInfoTruncated) {
+	return nil, nil, nil
+}
+
+func (m *mockedModel) RemoteNeedFolderFiles(device protocol.DeviceID, folder string, page, perpage int) ([]db.FileInfoTruncated, error) {
+	return nil, nil
 }

 func (m *mockedModel) NeedSize(folder string) db.Counts {
@@ -58,7 +66,7 @@ func (m *mockedModel) CurrentGlobalFile(folder string, file string) (protocol.Fi
 func (m *mockedModel) ResetFolder(folder string) {
 }

-func (m *mockedModel) Availability(folder, file string, version protocol.Vector, block protocol.BlockInfo) []model.Availability {
+func (m *mockedModel) Availability(folder string, file protocol.FileInfo, block protocol.BlockInfo) []model.Availability {
 	return nil
 }

@@ -70,6 +78,14 @@ func (m *mockedModel) SetIgnores(folder string, content []string) error {
 	return nil
 }

+func (m *mockedModel) GetFolderVersions(folder string) (map[string][]versioner.FileVersion, error) {
+	return nil, nil
+}
+
+func (m *mockedModel) RestoreFolderVersions(folder string, versions map[string]time.Time) (map[string]string, error) {
+	return nil, nil
+}
+
 func (m *mockedModel) PauseDevice(device protocol.DeviceID) {
 }

@@ -91,8 +107,8 @@ func (m *mockedModel) ScanFolderSubdirs(folder string, subs []string) error {

 func (m *mockedModel) BringToFront(folder, file string) {}

-func (m *mockedModel) ConnectedTo(deviceID protocol.DeviceID) bool {
-	return false
+func (m *mockedModel) Connection(deviceID protocol.DeviceID) (connections.Connection, bool) {
+	return nil, false
 }

 func (m *mockedModel) GlobalSize(folder string) db.Counts {
@@ -103,6 +119,10 @@ func (m *mockedModel) LocalSize(folder string) db.Counts {
 	return db.Counts{}
 }

+func (m *mockedModel) ReceiveOnlyChangedSize(folder string) db.Counts {
+	return db.Counts{}
+}
+
 func (m *mockedModel) CurrentSequence(folder string) (int64, bool) {
 	return 0, false
 }
@@ -114,3 +134,19 @@ func (m *mockedModel) RemoteSequence(folder string) (int64, bool) {
 func (m *mockedModel) State(folder string) (string, time.Time, error) {
 	return "", time.Time{}, nil
 }
+
+func (m *mockedModel) UsageReportingStats(version int, preview bool) map[string]interface{} {
+	return nil
+}
+
+func (m *mockedModel) FolderErrors(folder string) ([]model.FileError, error) {
+	return nil, nil
+}
+
+func (m *mockedModel) WatchError(folder string) error {
+	return nil
+}
+
+func (m *mockedModel) LocalChangedFiles(folder string, page, perpage int) []db.FileInfoTruncated {
+	return nil
+}
--- a/cmd/syncthing/monitor.go
+++ b/cmd/syncthing/monitor.go
@@ -17,6 +17,7 @@ import (
 	"syscall"
 	"time"

+	"github.com/syncthing/syncthing/lib/locations"
 	"github.com/syncthing/syncthing/lib/osutil"
 	"github.com/syncthing/syncthing/lib/sync"
 )
@@ -127,7 +128,7 @@ func monitorMain(runtimeOptions RuntimeOptions) {
 		select {
 		case s := <-stopSign:
 			l.Infof("Signal %d received; exiting", s)
-			cmd.Process.Kill()
+			cmd.Process.Signal(sigTerm)
 			<-exit
 			return

@@ -198,7 +199,7 @@ func copyStderr(stderr io.Reader, dst io.Writer) {
 			}

 			if strings.HasPrefix(line, "panic:") || strings.HasPrefix(line, "fatal error:") {
-				panicFd, err = os.Create(timestampedLoc(locPanicLog))
+				panicFd, err = os.Create(locations.GetTimestamped(locations.PanicLog))
 				if err != nil {
 					l.Warnln("Create panic log:", err)
 					continue
@@ -418,10 +419,10 @@ func (f *autoclosedFile) closerLoop() {
 func childEnv() []string {
 	var env []string
 	for _, str := range os.Environ() {
-		if strings.HasPrefix("STNORESTART=", str) {
+		if strings.HasPrefix(str, "STNORESTART=") {
 			continue
 		}
-		if strings.HasPrefix("STMONITORED=", str) {
+		if strings.HasPrefix(str, "STMONITORED=") {
 			continue
 		}
 		env = append(env, str)
--- a/cmd/syncthing/monitor_test.go
+++ b/cmd/syncthing/monitor_test.go
@@ -0,0 +1,88 @@
+// Copyright (C) 2017 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestAutoClosedFile(t *testing.T) {
+	os.RemoveAll("_autoclose")
+	defer os.RemoveAll("_autoclose")
+	os.Mkdir("_autoclose", 0755)
+	file := filepath.FromSlash("_autoclose/tmp")
+	data := []byte("hello, world\n")
+
+	// An autoclosed file that closes very quickly
+	ac := newAutoclosedFile(file, time.Millisecond, time.Millisecond)
+
+	// Write some data.
+	if _, err := ac.Write(data); err != nil {
+		t.Fatal(err)
+	}
+
+	// Wait for it to close
+	start := time.Now()
+	for {
+		time.Sleep(time.Millisecond)
+		ac.mut.Lock()
+		fd := ac.fd
+		ac.mut.Unlock()
+		if fd == nil {
+			break
+		}
+		if time.Since(start) > time.Second {
+			t.Fatal("File should have been closed after first write")
+		}
+	}
+
+	// Write more data, which should be an append.
+	if _, err := ac.Write(data); err != nil {
+		t.Fatal(err)
+	}
+
+	// Close.
+	if err := ac.Close(); err != nil {
+		t.Fatal(err)
+	}
+
+	// The file should have both writes in it.
+	bs, err := ioutil.ReadFile(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(bs) != 2*len(data) {
+		t.Fatalf("Writes failed, expected %d bytes, not %d", 2*len(data), len(bs))
+	}
+
+	// Open the file again.
+	ac = newAutoclosedFile(file, time.Second, time.Second)
+
+	// Write something
+	if _, err := ac.Write(data); err != nil {
+		t.Fatal(err)
+	}
+
+	// It should now contain only one write, because the first open
+	// should be a truncate.
+	bs, err = ioutil.ReadFile(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(bs) != len(data) {
+		t.Fatalf("Write failed, expected %d bytes, not %d", len(data), len(bs))
+	}
+
+	// Close.
+	if err := ac.Close(); err != nil {
+		t.Fatal(err)
+	}
+}
--- a/cmd/syncthing/perfstats_unix.go
+++ b/cmd/syncthing/perfstats_unix.go
@@ -38,7 +38,10 @@ func savePerfStats(file string) {

 	t0 := time.Now()
 	for t := range time.NewTicker(250 * time.Millisecond).C {
-		syscall.Getrusage(syscall.RUSAGE_SELF, &rusage)
+		if err := syscall.Getrusage(syscall.RUSAGE_SELF, &rusage); err != nil {
+			continue
+		}
+
 		curTime := time.Now().UnixNano()
 		timeDiff := curTime - prevTime
 		curUsage := rusage.Utime.Nano() + rusage.Stime.Nano()
--- a/cmd/syncthing/summaryservice.go
+++ b/cmd/syncthing/summaryservice.go
@@ -36,7 +36,9 @@ type folderSummaryService struct {

 func newFolderSummaryService(cfg configIntf, m modelIntf) *folderSummaryService {
 	service := &folderSummaryService{
-		Supervisor:      suture.NewSimple("folderSummaryService"),
+		Supervisor: suture.New("folderSummaryService", suture.Spec{
+			PassThroughPanics: true,
+		}),
 		cfg:             cfg,
 		model:           m,
 		stop:            make(chan struct{}),
@@ -60,7 +62,7 @@ func (c *folderSummaryService) Stop() {
 // listenForUpdates subscribes to the event bus and makes note of folders that
 // need their data recalculated.
 func (c *folderSummaryService) listenForUpdates() {
-	sub := events.Default.Subscribe(events.LocalIndexUpdated | events.RemoteIndexUpdated | events.StateChanged | events.RemoteDownloadProgress | events.DeviceConnected)
+	sub := events.Default.Subscribe(events.LocalIndexUpdated | events.RemoteIndexUpdated | events.StateChanged | events.RemoteDownloadProgress | events.DeviceConnected | events.FolderWatchStateChanged)
 	defer events.Default.Unsubscribe(sub)

 	for {
@@ -105,14 +107,14 @@ func (c *folderSummaryService) listenForUpdates() {
 					// c.immediate must be nonblocking so that we can continue
 					// handling events.

+					c.foldersMut.Lock()
 					select {
 					case c.immediate <- folder:
-						c.foldersMut.Lock()
 						delete(c.folders, folder)
-						c.foldersMut.Unlock()
-
 					default:
+						c.folders[folder] = struct{}{}
 					}
+					c.foldersMut.Unlock()
 				}

 			default:
@@ -187,7 +189,10 @@ func (c *folderSummaryService) foldersToHandle() []string {
 func (c *folderSummaryService) sendSummary(folder string) {
 	// The folder summary contains how many bytes, files etc
 	// are in the folder and how in sync we are.
-	data := folderSummary(c.cfg, c.model, folder)
+	data, err := folderSummary(c.cfg, c.model, folder)
+	if err != nil {
+		return
+	}
 	events.Default.Log(events.FolderSummary, map[string]interface{}{
 		"folder":  folder,
 		"summary": data,
@@ -198,21 +203,17 @@ func (c *folderSummaryService) sendSummary(folder string) {
 			// We already know about ourselves.
 			continue
 		}
-		if !c.model.ConnectedTo(devCfg.DeviceID) {
+		if _, ok := c.model.Connection(devCfg.DeviceID); !ok {
 			// We're not interested in disconnected devices.
 			continue
 		}

 		// Get completion percentage of this folder for the
 		// remote device.
-		comp := c.model.Completion(devCfg.DeviceID, folder)
-		events.Default.Log(events.FolderCompletion, map[string]interface{}{
-			"folder":      folder,
-			"device":      devCfg.DeviceID.String(),
-			"completion":  comp.CompletionPct,
-			"needBytes":   comp.NeedBytes,
-			"globalBytes": comp.GlobalBytes,
-		})
+		comp := jsonCompletion(c.model.Completion(devCfg.DeviceID, folder))
+		comp["folder"] = folder
+		comp["device"] = devCfg.DeviceID.String()
+		events.Default.Log(events.FolderCompletion, comp)
 	}
 }

--- a/cmd/syncthing/support_bundle.go
+++ b/cmd/syncthing/support_bundle.go
@@ -0,0 +1,47 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"archive/zip"
+	"io"
+
+	"github.com/syncthing/syncthing/lib/config"
+)
+
+// getRedactedConfig redacting some parts of config
+func getRedactedConfig(s *apiService) config.Configuration {
+	rawConf := s.cfg.RawCopy()
+	rawConf.GUI.APIKey = "REDACTED"
+	if rawConf.GUI.Password != "" {
+		rawConf.GUI.Password = "REDACTED"
+	}
+	if rawConf.GUI.User != "" {
+		rawConf.GUI.User = "REDACTED"
+	}
+	return rawConf
+}
+
+// writeZip writes a zip file containing the given entries
+func writeZip(writer io.Writer, files []fileEntry) error {
+	zipWriter := zip.NewWriter(writer)
+	defer zipWriter.Close()
+
+	for _, file := range files {
+		zipFile, err := zipWriter.Create(file.name)
+		if err != nil {
+			return err
+		}
+
+		_, err = zipFile.Write(file.data)
+		if err != nil {
+			return err
+		}
+	}
+
+	return zipWriter.Close()
+}
--- a/cmd/syncthing/usage_report.go
+++ b/cmd/syncthing/usage_report.go
@@ -12,82 +12,38 @@ import (
 	"crypto/rand"
 	"crypto/tls"
 	"encoding/json"
-	"fmt"
+	"net"
 	"net/http"
 	"runtime"
 	"sort"
 	"strings"
+	"sync"
 	"time"

+	"github.com/syncthing/syncthing/lib/build"
 	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/connections"
 	"github.com/syncthing/syncthing/lib/dialer"
 	"github.com/syncthing/syncthing/lib/model"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/scanner"
 	"github.com/syncthing/syncthing/lib/upgrade"
-	"github.com/thejerf/suture"
 )

 // Current version number of the usage report, for acceptance purposes. If
 // fields are added or changed this integer must be incremented so that users
 // are prompted for acceptance of the new report.
-const usageReportVersion = 2
-
-type usageReportingManager struct {
-	cfg   *config.Wrapper
-	model *model.Model
-	sup   *suture.Supervisor
-}
-
-func newUsageReportingManager(cfg *config.Wrapper, m *model.Model) *usageReportingManager {
-	mgr := &usageReportingManager{
-		cfg:   cfg,
-		model: m,
-	}
-
-	// Start UR if it's enabled.
-	mgr.CommitConfiguration(config.Configuration{}, cfg.RawCopy())
-
-	// Listen to future config changes so that we can start and stop as
-	// appropriate.
-	cfg.Subscribe(mgr)
-
-	return mgr
-}
-
-func (m *usageReportingManager) VerifyConfiguration(from, to config.Configuration) error {
-	return nil
-}
-
-func (m *usageReportingManager) CommitConfiguration(from, to config.Configuration) bool {
-	if to.Options.URAccepted >= usageReportVersion && m.sup == nil {
-		// Usage reporting was turned on; lets start it.
-		service := newUsageReportingService(m.cfg, m.model)
-		m.sup = suture.NewSimple("usageReporting")
-		m.sup.Add(service)
-		m.sup.ServeBackground()
-	} else if to.Options.URAccepted < usageReportVersion && m.sup != nil {
-		// Usage reporting was turned off
-		m.sup.Stop()
-		m.sup = nil
-	}
-
-	return true
-}
-
-func (m *usageReportingManager) String() string {
-	return fmt.Sprintf("usageReportingManager@%p", m)
-}
+const usageReportVersion = 3

 // reportData returns the data to be sent in a usage report. It's used in
 // various places, so not part of the usageReportingManager object.
-func reportData(cfg configIntf, m modelIntf) map[string]interface{} {
+func reportData(cfg configIntf, m modelIntf, connectionsService connectionsIntf, version int, preview bool) map[string]interface{} {
 	opts := cfg.Options()
 	res := make(map[string]interface{})
-	res["urVersion"] = usageReportVersion
+	res["urVersion"] = version
 	res["uniqueID"] = opts.URUniqueID
-	res["version"] = Version
-	res["longVersion"] = LongVersion
+	res["version"] = build.Version
+	res["longVersion"] = build.LongVersion
 	res["platform"] = runtime.GOOS + "-" + runtime.GOARCH
 	res["numFolders"] = len(cfg.Folders())
 	res["numDevices"] = len(cfg.Devices())
@@ -96,10 +52,10 @@ func reportData(cfg configIntf, m modelIntf) map[string]interface{} {
 	var totBytes, maxBytes int64
 	for folderID := range cfg.Folders() {
 		global := m.GlobalSize(folderID)
-		totFiles += global.Files
+		totFiles += int(global.Files)
 		totBytes += global.Bytes
-		if global.Files > maxFiles {
-			maxFiles = global.Files
+		if int(global.Files) > maxFiles {
+			maxFiles = int(global.Files)
 		}
 		if global.Bytes > maxBytes {
 			maxBytes = global.Bytes
@@ -125,7 +81,9 @@ func reportData(cfg configIntf, m modelIntf) map[string]interface{} {

 	var rescanIntvs []int
 	folderUses := map[string]int{
-		"readonly":            0,
+		"sendonly":            0,
+		"sendreceive":         0,
+		"receiveonly":         0,
 		"ignorePerms":         0,
 		"ignoreDelete":        0,
 		"autoNormalize":       0,
@@ -137,8 +95,13 @@ func reportData(cfg configIntf, m modelIntf) map[string]interface{} {
 	for _, cfg := range cfg.Folders() {
 		rescanIntvs = append(rescanIntvs, cfg.RescanIntervalS)

-		if cfg.Type == config.FolderTypeSendOnly {
-			folderUses["readonly"]++
+		switch cfg.Type {
+		case config.FolderTypeSendOnly:
+			folderUses["sendonly"]++
+		case config.FolderTypeSendReceive:
+			folderUses["sendreceive"]++
+		case config.FolderTypeReceiveOnly:
+			folderUses["receiveonly"]++
 		}
 		if cfg.IgnorePerms {
 			folderUses["ignorePerms"]++
@@ -227,27 +190,168 @@ func reportData(cfg configIntf, m modelIntf) map[string]interface{} {
 	res["upgradeAllowedAuto"] = !(upgrade.DisabledByCompilation || noUpgradeFromEnv) && opts.AutoUpgradeIntervalH > 0
 	res["upgradeAllowedPre"] = !(upgrade.DisabledByCompilation || noUpgradeFromEnv) && opts.AutoUpgradeIntervalH > 0 && opts.UpgradeToPreReleases

+	if version >= 3 {
+		res["uptime"] = int(time.Since(startTime).Seconds())
+		res["natType"] = connectionsService.NATType()
+		res["alwaysLocalNets"] = len(opts.AlwaysLocalNets) > 0
+		res["cacheIgnoredFiles"] = opts.CacheIgnoredFiles
+		res["overwriteRemoteDeviceNames"] = opts.OverwriteRemoteDevNames
+		res["progressEmitterEnabled"] = opts.ProgressUpdateIntervalS > -1
+		res["customDefaultFolderPath"] = opts.DefaultFolderPath != "~"
+		res["customTrafficClass"] = opts.TrafficClass != 0
+		res["customTempIndexMinBlocks"] = opts.TempIndexMinBlocks != 10
+		res["temporariesDisabled"] = opts.KeepTemporariesH == 0
+		res["temporariesCustom"] = opts.KeepTemporariesH != 24
+		res["limitBandwidthInLan"] = opts.LimitBandwidthInLan
+		res["customReleaseURL"] = opts.ReleasesURL != "https://upgrades.syncthing.net/meta.json"
+		res["restartOnWakeup"] = opts.RestartOnWakeup
+
+		folderUsesV3 := map[string]int{
+			"scanProgressDisabled":    0,
+			"conflictsDisabled":       0,
+			"conflictsUnlimited":      0,
+			"conflictsOther":          0,
+			"disableSparseFiles":      0,
+			"disableTempIndexes":      0,
+			"alwaysWeakHash":          0,
+			"customWeakHashThreshold": 0,
+			"fsWatcherEnabled":        0,
+		}
+		pullOrder := make(map[string]int)
+		filesystemType := make(map[string]int)
+		var fsWatcherDelays []int
+		for _, cfg := range cfg.Folders() {
+			if cfg.ScanProgressIntervalS < 0 {
+				folderUsesV3["scanProgressDisabled"]++
+			}
+			if cfg.MaxConflicts == 0 {
+				folderUsesV3["conflictsDisabled"]++
+			} else if cfg.MaxConflicts < 0 {
+				folderUsesV3["conflictsUnlimited"]++
+			} else {
+				folderUsesV3["conflictsOther"]++
+			}
+			if cfg.DisableSparseFiles {
+				folderUsesV3["disableSparseFiles"]++
+			}
+			if cfg.DisableTempIndexes {
+				folderUsesV3["disableTempIndexes"]++
+			}
+			if cfg.WeakHashThresholdPct < 0 {
+				folderUsesV3["alwaysWeakHash"]++
+			} else if cfg.WeakHashThresholdPct != 25 {
+				folderUsesV3["customWeakHashThreshold"]++
+			}
+			if cfg.FSWatcherEnabled {
+				folderUsesV3["fsWatcherEnabled"]++
+			}
+			pullOrder[cfg.Order.String()]++
+			filesystemType[cfg.FilesystemType.String()]++
+			fsWatcherDelays = append(fsWatcherDelays, cfg.FSWatcherDelayS)
+		}
+		sort.Ints(fsWatcherDelays)
+		folderUsesV3Interface := map[string]interface{}{
+			"pullOrder":       pullOrder,
+			"filesystemType":  filesystemType,
+			"fsWatcherDelays": fsWatcherDelays,
+		}
+		for key, value := range folderUsesV3 {
+			folderUsesV3Interface[key] = value
+		}
+		res["folderUsesV3"] = folderUsesV3Interface
+
+		guiCfg := cfg.GUI()
+		// Anticipate multiple GUI configs in the future, hence store counts.
+		guiStats := map[string]int{
+			"enabled":                   0,
+			"useTLS":                    0,
+			"useAuth":                   0,
+			"insecureAdminAccess":       0,
+			"debugging":                 0,
+			"insecureSkipHostCheck":     0,
+			"insecureAllowFrameLoading": 0,
+			"listenLocal":               0,
+			"listenUnspecified":         0,
+		}
+		theme := make(map[string]int)
+		if guiCfg.Enabled {
+			guiStats["enabled"]++
+			if guiCfg.UseTLS() {
+				guiStats["useTLS"]++
+			}
+			if len(guiCfg.User) > 0 && len(guiCfg.Password) > 0 {
+				guiStats["useAuth"]++
+			}
+			if guiCfg.InsecureAdminAccess {
+				guiStats["insecureAdminAccess"]++
+			}
+			if guiCfg.Debugging {
+				guiStats["debugging"]++
+			}
+			if guiCfg.InsecureSkipHostCheck {
+				guiStats["insecureSkipHostCheck"]++
+			}
+			if guiCfg.InsecureAllowFrameLoading {
+				guiStats["insecureAllowFrameLoading"]++
+			}
+
+			addr, err := net.ResolveTCPAddr("tcp", guiCfg.Address())
+			if err == nil {
+				if addr.IP.IsLoopback() {
+					guiStats["listenLocal"]++
+				} else if addr.IP.IsUnspecified() {
+					guiStats["listenUnspecified"]++
+				}
+			}
+
+			theme[guiCfg.Theme]++
+		}
+		guiStatsInterface := map[string]interface{}{
+			"theme": theme,
+		}
+		for key, value := range guiStats {
+			guiStatsInterface[key] = value
+		}
+		res["guiStats"] = guiStatsInterface
+	}
+
+	for key, value := range m.UsageReportingStats(version, preview) {
+		res[key] = value
+	}
+
 	return res
 }

 type usageReportingService struct {
-	cfg   *config.Wrapper
-	model *model.Model
-	stop  chan struct{}
+	cfg                *config.Wrapper
+	model              *model.Model
+	connectionsService *connections.Service
+	forceRun           chan struct{}
+	stop               chan struct{}
+	stopped            chan struct{}
+	stopMut            sync.RWMutex
 }

-func newUsageReportingService(cfg *config.Wrapper, model *model.Model) *usageReportingService {
-	return &usageReportingService{
-		cfg:   cfg,
-		model: model,
-		stop:  make(chan struct{}),
+func newUsageReportingService(cfg *config.Wrapper, model *model.Model, connectionsService *connections.Service) *usageReportingService {
+	svc := &usageReportingService{
+		cfg:                cfg,
+		model:              model,
+		connectionsService: connectionsService,
+		forceRun:           make(chan struct{}),
+		stop:               make(chan struct{}),
+		stopped:            make(chan struct{}),
 	}
+	close(svc.stopped) // Not yet running, dont block on Stop()
+	cfg.Subscribe(svc)
+	return svc
 }

 func (s *usageReportingService) sendUsageReport() error {
-	d := reportData(s.cfg, s.model)
+	d := reportData(s.cfg, s.model, s.connectionsService, s.cfg.Options().URAccepted, false)
 	var b bytes.Buffer
-	json.NewEncoder(&b).Encode(d)
+	if err := json.NewEncoder(&b).Encode(d); err != nil {
+		return err
+	}

 	client := &http.Client{
 		Transport: &http.Transport{
@@ -263,33 +367,66 @@ func (s *usageReportingService) sendUsageReport() error {
 }

 func (s *usageReportingService) Serve() {
+	s.stopMut.Lock()
 	s.stop = make(chan struct{})
-
-	l.Infoln("Starting usage reporting")
-	defer l.Infoln("Stopping usage reporting")
-
-	t := time.NewTimer(time.Duration(s.cfg.Options().URInitialDelayS) * time.Second) // time to initial report at start
+	s.stopped = make(chan struct{})
+	s.stopMut.Unlock()
+	t := time.NewTimer(time.Duration(s.cfg.Options().URInitialDelayS) * time.Second)
+	s.stopMut.RLock()
+	defer func() {
+		close(s.stopped)
+		s.stopMut.RUnlock()
+	}()
 	for {
 		select {
 		case <-s.stop:
 			return
+		case <-s.forceRun:
+			t.Reset(0)
 		case <-t.C:
-			err := s.sendUsageReport()
-			if err != nil {
-				l.Infoln("Usage report:", err)
+			if s.cfg.Options().URAccepted >= 2 {
+				err := s.sendUsageReport()
+				if err != nil {
+					l.Infoln("Usage report:", err)
+				} else {
+					l.Infof("Sent usage report (version %d)", s.cfg.Options().URAccepted)
+				}
 			}
 			t.Reset(24 * time.Hour) // next report tomorrow
 		}
 	}
 }

+func (s *usageReportingService) VerifyConfiguration(from, to config.Configuration) error {
+	return nil
+}
+
+func (s *usageReportingService) CommitConfiguration(from, to config.Configuration) bool {
+	if from.Options.URAccepted != to.Options.URAccepted || from.Options.URUniqueID != to.Options.URUniqueID || from.Options.URURL != to.Options.URURL {
+		s.stopMut.RLock()
+		select {
+		case s.forceRun <- struct{}{}:
+		case <-s.stop:
+		}
+		s.stopMut.RUnlock()
+	}
+	return true
+}
+
 func (s *usageReportingService) Stop() {
+	s.stopMut.RLock()
 	close(s.stop)
+	<-s.stopped
+	s.stopMut.RUnlock()
+}
+
+func (*usageReportingService) String() string {
+	return "usageReportingService"
 }

 // cpuBench returns CPU performance as a measure of single threaded SHA-256 MiB/s
 func cpuBench(iterations int, duration time.Duration, useWeakHash bool) float64 {
-	dataSize := 16 * protocol.BlockSize
+	dataSize := 16 * protocol.MinBlockSize
 	bs := make([]byte, dataSize)
 	rand.Reader.Read(bs)

@@ -310,7 +447,7 @@ func cpuBenchOnce(duration time.Duration, useWeakHash bool, bs []byte) float64 {
 	b := 0
 	for time.Since(t0) < duration {
 		r := bytes.NewReader(bs)
-		blocksResult, _ = scanner.Blocks(context.TODO(), r, protocol.BlockSize, int64(len(bs)), nil, useWeakHash)
+		blocksResult, _ = scanner.Blocks(context.TODO(), r, protocol.MinBlockSize, int64(len(bs)), nil, useWeakHash)
 		b += len(bs)
 	}
 	d := time.Since(t0)
--- a/cmd/syncthing/verboseservice.go
+++ b/cmd/syncthing/verboseservice.go
@@ -105,7 +105,7 @@ func (s *verboseService) formatEvent(ev events.Event) string {
 		return fmt.Sprintf("Device %v sent an index update for %q with %d items", data["device"], data["folder"], data["items"])

 	case events.DeviceRejected:
-		data := ev.Data.(map[string]interface{})
+		data := ev.Data.(map[string]string)
 		return fmt.Sprintf("Rejected connection from device %v at %v", data["device"], data["address"])

 	case events.FolderRejected:
--- a/cmd/uraggregate/main.go
+++ b/cmd/uraggregate/main.go
@@ -0,0 +1,330 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"database/sql"
+	"log"
+	"os"
+	"time"
+
+	_ "github.com/lib/pq"
+)
+
+var dbConn = getEnvDefault("UR_DB_URL", "postgres://user:password@localhost/ur?sslmode=disable")
+
+func getEnvDefault(key, def string) string {
+	if val := os.Getenv(key); val != "" {
+		return val
+	}
+	return def
+}
+
+func main() {
+	log.SetFlags(log.Ltime | log.Ldate)
+	log.SetOutput(os.Stdout)
+
+	db, err := sql.Open("postgres", dbConn)
+	if err != nil {
+		log.Fatalln("database:", err)
+	}
+	err = setupDB(db)
+	if err != nil {
+		log.Fatalln("database:", err)
+	}
+
+	for {
+		runAggregation(db)
+		// Sleep until one minute past next midnight
+		sleepUntilNext(24*time.Hour, 1*time.Minute)
+	}
+}
+
+func runAggregation(db *sql.DB) {
+	since := maxIndexedDay(db, "VersionSummary")
+	log.Println("Aggregating VersionSummary data since", since)
+	rows, err := aggregateVersionSummary(db, since)
+	if err != nil {
+		log.Fatalln("aggregate:", err)
+	}
+	log.Println("Inserted", rows, "rows")
+
+	log.Println("Aggregating UserMovement data")
+	rows, err = aggregateUserMovement(db)
+	if err != nil {
+		log.Fatalln("aggregate:", err)
+	}
+	log.Println("Inserted", rows, "rows")
+
+	log.Println("Aggregating Performance data")
+	since = maxIndexedDay(db, "Performance")
+	rows, err = aggregatePerformance(db, since)
+	if err != nil {
+		log.Fatalln("aggregate:", err)
+	}
+	log.Println("Inserted", rows, "rows")
+
+	log.Println("Aggregating BlockStats data")
+	since = maxIndexedDay(db, "BlockStats")
+	rows, err = aggregateBlockStats(db, since)
+	if err != nil {
+		log.Fatalln("aggregate:", err)
+	}
+	log.Println("Inserted", rows, "rows")
+}
+
+func sleepUntilNext(intv, margin time.Duration) {
+	now := time.Now().UTC()
+	next := now.Truncate(intv).Add(intv).Add(margin)
+	log.Println("Sleeping until", next)
+	time.Sleep(next.Sub(now))
+}
+
+func setupDB(db *sql.DB) error {
+	_, err := db.Exec(`CREATE TABLE IF NOT EXISTS VersionSummary (
+		Day TIMESTAMP NOT NULL,
+		Version VARCHAR(8) NOT NULL,
+		Count INTEGER NOT NULL
+	)`)
+	if err != nil {
+		return err
+	}
+
+	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS UserMovement (
+		Day TIMESTAMP NOT NULL,
+		Added INTEGER NOT NULL,
+		Bounced INTEGER NOT NULL,
+		Removed INTEGER NOT NULL
+	)`)
+	if err != nil {
+		return err
+	}
+
+	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS Performance (
+		Day TIMESTAMP NOT NULL,
+		TotFiles INTEGER NOT NULL,
+		TotMiB INTEGER NOT NULL,
+		SHA256Perf DOUBLE PRECISION NOT NULL,
+		MemorySize INTEGER NOT NULL,
+		MemoryUsageMiB INTEGER NOT NULL
+	)`)
+	if err != nil {
+		return err
+	}
+
+	_, err = db.Exec(`CREATE TABLE IF NOT EXISTS BlockStats (
+		Day TIMESTAMP NOT NULL,
+		Reports INTEGER NOT NULL,
+		Total INTEGER NOT NULL,
+		Renamed INTEGER NOT NULL,
+		Reused INTEGER NOT NULL,
+		Pulled INTEGER NOT NULL,
+		CopyOrigin INTEGER NOT NULL,
+		CopyOriginShifted INTEGER NOT NULL,
+		CopyElsewhere INTEGER NOT NULL
+	)`)
+	if err != nil {
+		return err
+	}
+
+	var t string
+
+	row := db.QueryRow(`SELECT 'UniqueDayVersionIndex'::regclass`)
+	if err := row.Scan(&t); err != nil {
+		_, err = db.Exec(`CREATE UNIQUE INDEX UniqueDayVersionIndex ON VersionSummary (Day, Version)`)
+	}
+
+	row = db.QueryRow(`SELECT 'VersionDayIndex'::regclass`)
+	if err := row.Scan(&t); err != nil {
+		_, err = db.Exec(`CREATE INDEX VersionDayIndex ON VersionSummary (Day)`)
+	}
+
+	row = db.QueryRow(`SELECT 'MovementDayIndex'::regclass`)
+	if err := row.Scan(&t); err != nil {
+		_, err = db.Exec(`CREATE INDEX MovementDayIndex ON UserMovement (Day)`)
+	}
+
+	row = db.QueryRow(`SELECT 'PerformanceDayIndex'::regclass`)
+	if err := row.Scan(&t); err != nil {
+		_, err = db.Exec(`CREATE INDEX PerformanceDayIndex ON Performance (Day)`)
+	}
+
+	row = db.QueryRow(`SELECT 'BlockStatsDayIndex'::regclass`)
+	if err := row.Scan(&t); err != nil {
+		_, err = db.Exec(`CREATE INDEX BlockStatsDayIndex ON BlockStats (Day)`)
+	}
+
+	return err
+}
+
+func maxIndexedDay(db *sql.DB, table string) time.Time {
+	var t time.Time
+	row := db.QueryRow("SELECT MAX(Day) FROM " + table)
+	err := row.Scan(&t)
+	if err != nil {
+		return time.Time{}
+	}
+	return t
+}
+
+func aggregateVersionSummary(db *sql.DB, since time.Time) (int64, error) {
+	res, err := db.Exec(`INSERT INTO VersionSummary (
+	SELECT
+		DATE_TRUNC('day', Received) AS Day,
+		SUBSTRING(Version FROM '^v\d.\d+') AS Ver,
+		COUNT(*) AS Count
+		FROM Reports
+		WHERE
+			DATE_TRUNC('day', Received) > $1
+			AND DATE_TRUNC('day', Received) < DATE_TRUNC('day', NOW())
+			AND Version like 'v_.%'
+		GROUP BY Day, Ver
+		);
+	`, since)
+	if err != nil {
+		return 0, err
+	}
+
+	return res.RowsAffected()
+}
+
+func aggregateUserMovement(db *sql.DB) (int64, error) {
+	rows, err := db.Query(`SELECT
+		DATE_TRUNC('day', Received) AS Day,
+		UniqueID
+		FROM Reports
+		WHERE
+			DATE_TRUNC('day', Received) < DATE_TRUNC('day', NOW())
+			AND Version like 'v_.%'
+		ORDER BY Day
+	`)
+	if err != nil {
+		return 0, err
+	}
+	defer rows.Close()
+
+	firstSeen := make(map[string]time.Time)
+	lastSeen := make(map[string]time.Time)
+	var minTs time.Time
+	minTs = minTs.In(time.UTC)
+
+	for rows.Next() {
+		var ts time.Time
+		var id string
+		if err := rows.Scan(&ts, &id); err != nil {
+			return 0, err
+		}
+
+		if minTs.IsZero() {
+			minTs = ts
+		}
+		if _, ok := firstSeen[id]; !ok {
+			firstSeen[id] = ts
+		}
+		lastSeen[id] = ts
+	}
+
+	type sumRow struct {
+		day     time.Time
+		added   int
+		removed int
+		bounced int
+	}
+	var sumRows []sumRow
+	for t := minTs; t.Before(time.Now().Truncate(24 * time.Hour)); t = t.AddDate(0, 0, 1) {
+		var added, removed, bounced int
+		old := t.Before(time.Now().AddDate(0, 0, -30))
+		for id, first := range firstSeen {
+			last := lastSeen[id]
+			if first.Equal(t) && last.Equal(t) && old {
+				bounced++
+				continue
+			}
+			if first.Equal(t) {
+				added++
+			}
+			if last == t && old {
+				removed++
+			}
+		}
+		sumRows = append(sumRows, sumRow{t, added, removed, bounced})
+	}
+
+	tx, err := db.Begin()
+	if err != nil {
+		return 0, err
+	}
+	if _, err := tx.Exec("DELETE FROM UserMovement"); err != nil {
+		tx.Rollback()
+		return 0, err
+	}
+	for _, r := range sumRows {
+		if _, err := tx.Exec("INSERT INTO UserMovement (Day, Added, Removed, Bounced) VALUES ($1, $2, $3, $4)", r.day, r.added, r.removed, r.bounced); err != nil {
+			tx.Rollback()
+			return 0, err
+		}
+	}
+
+	return int64(len(sumRows)), tx.Commit()
+}
+
+func aggregatePerformance(db *sql.DB, since time.Time) (int64, error) {
+	res, err := db.Exec(`INSERT INTO Performance (
+	SELECT
+		DATE_TRUNC('day', Received) AS Day,
+		AVG(TotFiles) As TotFiles,
+		AVG(TotMiB) As TotMiB,
+		AVG(SHA256Perf) As SHA256Perf,
+		AVG(MemorySize) As MemorySize,
+		AVG(MemoryUsageMiB) As MemoryUsageMiB
+		FROM Reports
+		WHERE
+			DATE_TRUNC('day', Received) > $1
+			AND DATE_TRUNC('day', Received) < DATE_TRUNC('day', NOW())
+			AND Version like 'v_.%'
+		GROUP BY Day
+		);
+	`, since)
+	if err != nil {
+		return 0, err
+	}
+
+	return res.RowsAffected()
+}
+
+func aggregateBlockStats(db *sql.DB, since time.Time) (int64, error) {
+	// Filter out anything prior 0.14.41 as that has sum aggregations which
+	// made no sense.
+	res, err := db.Exec(`INSERT INTO BlockStats (
+	SELECT
+		DATE_TRUNC('day', Received) AS Day,
+		COUNT(1) As Reports,
+		SUM(BlocksTotal) AS Total,
+		SUM(BlocksRenamed) AS Renamed,
+		SUM(BlocksReused) AS Reused,
+		SUM(BlocksPulled) AS Pulled,
+		SUM(BlocksCopyOrigin) AS CopyOrigin,
+		SUM(BlocksCopyOriginShifted) AS CopyOriginShifted,
+		SUM(BlocksCopyElsewhere) AS CopyElsewhere
+		FROM Reports
+		WHERE
+			DATE_TRUNC('day', Received) > $1
+			AND DATE_TRUNC('day', Received) < DATE_TRUNC('day', NOW())
+			AND ReportVersion = 3
+			AND Version like 'v_.%'
+			AND Version NOT LIKE 'v0.14.40%'
+			AND Version NOT LIKE 'v0.14.39%'
+			AND Version NOT LIKE 'v0.14.38%'
+		GROUP BY Day
+	);
+	`, since)
+	if err != nil {
+		return 0, err
+	}
+
+	return res.RowsAffected()
+}
--- a/cmd/ursrv/analytics.go
+++ b/cmd/ursrv/analytics.go
@@ -0,0 +1,240 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+type analytic struct {
+	Key        string
+	Count      int
+	Percentage float64
+	Items      []analytic `json:",omitempty"`
+}
+
+type analyticList []analytic
+
+func (l analyticList) Less(a, b int) bool {
+	if l[a].Key == "Others" {
+		return true
+	}
+	if l[b].Key == "Others" {
+		return false
+	}
+	return l[b].Count < l[a].Count // inverse
+}
+
+func (l analyticList) Swap(a, b int) {
+	l[a], l[b] = l[b], l[a]
+}
+
+func (l analyticList) Len() int {
+	return len(l)
+}
+
+// Returns a list of frequency analytics for a given list of strings.
+func analyticsFor(ss []string, cutoff int) []analytic {
+	m := make(map[string]int)
+	t := 0
+	for _, s := range ss {
+		m[s]++
+		t++
+	}
+
+	l := make([]analytic, 0, len(m))
+	for k, c := range m {
+		l = append(l, analytic{
+			Key:        k,
+			Count:      c,
+			Percentage: 100 * float64(c) / float64(t),
+		})
+	}
+
+	sort.Sort(analyticList(l))
+
+	if cutoff > 0 && len(l) > cutoff {
+		c := 0
+		for _, i := range l[cutoff:] {
+			c += i.Count
+		}
+		l = append(l[:cutoff], analytic{
+			Key:        "Others",
+			Count:      c,
+			Percentage: 100 * float64(c) / float64(t),
+		})
+	}
+
+	return l
+}
+
+// Find the points at which certain penetration levels are met
+func penetrationLevels(as []analytic, points []float64) []analytic {
+	sort.Slice(as, func(a, b int) bool {
+		return versionLess(as[b].Key, as[a].Key)
+	})
+
+	var res []analytic
+
+	idx := 0
+	sum := 0.0
+	for _, a := range as {
+		sum += a.Percentage
+		if sum >= points[idx] {
+			a.Count = int(points[idx])
+			a.Percentage = sum
+			res = append(res, a)
+			idx++
+			if idx == len(points) {
+				break
+			}
+		}
+	}
+	return res
+}
+
+func statsForInts(data []int) [4]float64 {
+	var res [4]float64
+	if len(data) == 0 {
+		return res
+	}
+
+	sort.Ints(data)
+	res[0] = float64(data[int(float64(len(data))*0.05)])
+	res[1] = float64(data[len(data)/2])
+	res[2] = float64(data[int(float64(len(data))*0.95)])
+	res[3] = float64(data[len(data)-1])
+	return res
+}
+
+func statsForFloats(data []float64) [4]float64 {
+	var res [4]float64
+	if len(data) == 0 {
+		return res
+	}
+
+	sort.Float64s(data)
+	res[0] = data[int(float64(len(data))*0.05)]
+	res[1] = data[len(data)/2]
+	res[2] = data[int(float64(len(data))*0.95)]
+	res[3] = data[len(data)-1]
+	return res
+}
+
+func group(by func(string) string, as []analytic, perGroup int) []analytic {
+	var res []analytic
+
+next:
+	for _, a := range as {
+		group := by(a.Key)
+		for i := range res {
+			if res[i].Key == group {
+				res[i].Count += a.Count
+				res[i].Percentage += a.Percentage
+				if len(res[i].Items) < perGroup {
+					res[i].Items = append(res[i].Items, a)
+				}
+				continue next
+			}
+		}
+		res = append(res, analytic{
+			Key:        group,
+			Count:      a.Count,
+			Percentage: a.Percentage,
+			Items:      []analytic{a},
+		})
+	}
+
+	sort.Sort(analyticList(res))
+	return res
+}
+
+func byVersion(s string) string {
+	parts := strings.Split(s, ".")
+	if len(parts) >= 2 {
+		return strings.Join(parts[:2], ".")
+	}
+	return s
+}
+
+func byPlatform(s string) string {
+	parts := strings.Split(s, "-")
+	if len(parts) >= 2 {
+		return parts[0]
+	}
+	return s
+}
+
+var numericGoVersion = regexp.MustCompile(`^go[0-9]\.[0-9]+`)
+
+func byCompiler(s string) string {
+	if m := numericGoVersion.FindString(s); m != "" {
+		return m
+	}
+	return "Other"
+}
+
+func versionLess(a, b string) bool {
+	arel, apre := versionParts(a)
+	brel, bpre := versionParts(b)
+
+	minlen := len(arel)
+	if l := len(brel); l < minlen {
+		minlen = l
+	}
+
+	for i := 0; i < minlen; i++ {
+		if arel[i] != brel[i] {
+			return arel[i] < brel[i]
+		}
+	}
+
+	// Longer version is newer, when the preceding parts are equal
+	if len(arel) != len(brel) {
+		return len(arel) < len(brel)
+	}
+
+	if apre != bpre {
+		// "(+dev)" versions are ahead
+		if apre == plusStr {
+			return false
+		}
+		if bpre == plusStr {
+			return true
+		}
+		return apre < bpre
+	}
+
+	// don't actually care how the prerelease stuff compares for our purposes
+	return false
+}
+
+// Split a version as returned from transformVersion into parts.
+// "1.2.3-beta.2" -> []int{1, 2, 3}, "beta.2"}
+func versionParts(v string) ([]int, string) {
+	parts := strings.SplitN(v[1:], " ", 2) // " (+dev)" versions
+	if len(parts) == 1 {
+		parts = strings.SplitN(parts[0], "-", 2) // "-rc.1" type versions
+	}
+	fields := strings.Split(parts[0], ".")
+
+	release := make([]int, len(fields))
+	for i, s := range fields {
+		v, _ := strconv.Atoi(s)
+		release[i] = v
+	}
+
+	var prerelease string
+	if len(parts) > 1 {
+		prerelease = parts[1]
+	}
+
+	return release, prerelease
+}
--- a/cmd/ursrv/compiler_test.go
+++ b/cmd/ursrv/compiler_test.go
@@ -0,0 +1,31 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import "testing"
+
+func TestCompilerRe(t *testing.T) {
+	tests := [][3]string{
+		{`syncthing v0.11.0 (xgcc (Ubuntu 4.9.3-0ubuntu4) 4.9.3 linux-amd64 default) niklas@Niklas-Netbook 2015-04-26 13:15:08 UTC`, "xgcc (Ubuntu 4.9.3-0ubuntu4) 4.9.3", "niklas@Niklas-Netbook"},
+		{`syncthing v0.12.0-rc5 "Beryllium Bedbug" (go1.4.2 linux-arm android) unknown-user@Felix-T420 2015-10-22 18:32:15 UTC`, "go1.4.2", "unknown-user@Felix-T420"},
+		{`syncthing v0.13.0-beta.0+39-ge267bf3 "Copper Cockroach" (go1.4.2 linux-amd64) portage@slevermann.de 2016-01-20 08:41:52 UTC`, "go1.4.2", "portage@slevermann.de"},
+	}
+
+	for _, tc := range tests {
+		m := compilerRe.FindStringSubmatch(tc[0])
+		if len(m) != 3 {
+			t.Errorf("Regexp didn't match %q", tc[0])
+			continue
+		}
+		if m[1] != tc[1] {
+			t.Errorf("Compiler %q != %q", m[1], tc[1])
+		}
+		if m[2] != tc[2] {
+			t.Errorf("Builder %q != %q", m[2], tc[2])
+		}
+	}
+}
--- a/cmd/ursrv/formatting.go
+++ b/cmd/ursrv/formatting.go
@@ -0,0 +1,128 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"strings"
+)
+
+type NumberType int
+
+const (
+	NumberMetric NumberType = iota
+	NumberBinary
+	NumberDuration
+)
+
+func number(ntype NumberType, v float64) string {
+	if ntype == NumberDuration {
+		return duration(v)
+	} else if ntype == NumberBinary {
+		return binary(v)
+	} else {
+		return metric(v)
+	}
+}
+
+type suffix struct {
+	Suffix     string
+	Multiplier float64
+}
+
+var metricSuffixes = []suffix{
+	{"G", 1e9},
+	{"M", 1e6},
+	{"k", 1e3},
+}
+
+var binarySuffixes = []suffix{
+	{"Gi", 1 << 30},
+	{"Mi", 1 << 20},
+	{"Ki", 1 << 10},
+}
+
+var durationSuffix = []suffix{
+	{"year", 365 * 24 * 60 * 60},
+	{"month", 30 * 24 * 60 * 60},
+	{"day", 24 * 60 * 60},
+	{"hour", 60 * 60},
+	{"minute", 60},
+	{"second", 1},
+}
+
+func metric(v float64) string {
+	return withSuffix(v, metricSuffixes, false)
+}
+
+func binary(v float64) string {
+	return withSuffix(v, binarySuffixes, false)
+}
+
+func duration(v float64) string {
+	return withSuffix(v, durationSuffix, true)
+}
+
+func withSuffix(v float64, ps []suffix, pluralize bool) string {
+	for _, p := range ps {
+		if v >= p.Multiplier {
+			suffix := p.Suffix
+			if pluralize && v/p.Multiplier != 1.0 {
+				suffix += "s"
+			}
+			// If the number only has decimal zeroes, strip em off.
+			num := strings.TrimRight(strings.TrimRight(fmt.Sprintf("%.1f", v/p.Multiplier), "0"), ".")
+			return fmt.Sprintf("%s %s", num, suffix)
+		}
+	}
+	return strings.TrimRight(strings.TrimRight(fmt.Sprintf("%.1f", v), "0"), ".")
+}
+
+// commatize returns a number with sep as thousands separators. Handles
+// integers and plain floats.
+func commatize(sep, s string) string {
+	// If no dot, don't do anything.
+	if !strings.ContainsRune(s, '.') {
+		return s
+	}
+	var b bytes.Buffer
+	fs := strings.SplitN(s, ".", 2)
+
+	l := len(fs[0])
+	for i := range fs[0] {
+		b.Write([]byte{s[i]})
+		if i < l-1 && (l-i)%3 == 1 {
+			b.WriteString(sep)
+		}
+	}
+
+	if len(fs) > 1 && len(fs[1]) > 0 {
+		b.WriteString(".")
+		b.WriteString(fs[1])
+	}
+
+	return b.String()
+}
+
+func proportion(m map[string]int, count int) float64 {
+	total := 0
+	isMax := true
+	for _, n := range m {
+		total += n
+		if n > count {
+			isMax = false
+		}
+	}
+	pct := (100 * float64(count)) / float64(total)
+	// To avoid rounding errors in the template, surpassing 100% and breaking
+	// the progress bars.
+	if isMax && len(m) > 1 && count != total {
+		pct -= 0.01
+	}
+	return pct
+}
--- a/cmd/ursrv/main.go
+++ b/cmd/ursrv/main.go
--- a/cmd/ursrv/static/assets/img/favicon.png
+++ b/cmd/ursrv/static/assets/img/favicon.png
--- a/cmd/ursrv/static/bootstrap/css/bootstrap-theme.min.css
+++ b/cmd/ursrv/static/bootstrap/css/bootstrap-theme.min.css
--- a/cmd/ursrv/static/bootstrap/css/bootstrap.min.css
+++ b/cmd/ursrv/static/bootstrap/css/bootstrap.min.css
--- a/Show More
+++ b/Show More