diff --git a/app/flatpak-builtins-add-remote.c b/app/flatpak-builtins-add-remote.c
index 60651ec24..34f63717d 100644
--- a/app/flatpak-builtins-add-remote.c
+++ b/app/flatpak-builtins-add-remote.c
@@ -48,6 +48,7 @@ static int opt_prio = -1;
 static char *opt_title;
 static char *opt_default_branch;
 static char *opt_url;
+static char *opt_collection_id = NULL;
 static gboolean opt_from;
 static char **opt_gpg_import;
 
@@ -75,6 +76,9 @@ static GOptionEntry common_options[] = {
   { "prio", 0, 0, G_OPTION_ARG_INT, &opt_prio, N_("Set priority (default 1, higher is more prioritized)"), N_("PRIORITY") },
   { "title", 0, 0, G_OPTION_ARG_STRING, &opt_title, N_("A nice name to use for this remote"), N_("TITLE") },
   { "default-branch", 0, 0, G_OPTION_ARG_STRING, &opt_default_branch, N_("Default branch to use for this remote"), N_("BRANCH") },
+#ifdef FLATPAK_ENABLE_P2P
+  { "collection-id", 0, 0, G_OPTION_ARG_STRING, &opt_collection_id, N_("Collection ID"), N_("COLLECTION-ID") },
+#endif  /* FLATPAK_ENABLE_P2P */
   { "gpg-import", 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &opt_gpg_import, N_("Import GPG key from FILE (- for stdin)"), N_("FILE") },
   { "disable", 0, 0, G_OPTION_ARG_NONE, &opt_disable, N_("Disable the remote"), NULL },
   { "oci", 0, 0, G_OPTION_ARG_NONE, &opt_oci, N_("Add OCI registry"), NULL },
@@ -111,6 +115,12 @@ get_config_from_opts (FlatpakDir *dir, const char *remote_name, gboolean *change
       *changed = TRUE;
     }
 
+  if (opt_collection_id)
+    {
+      g_key_file_set_string (config, group, "collection-id", opt_collection_id);
+      *changed = TRUE;
+    }
+
   if (opt_title)
     {
       g_key_file_set_string (config, group, "xa.title", opt_title);
@@ -237,6 +247,12 @@ load_options (const char *filename,
   if (str != NULL)
     opt_url = str;
 
+#ifdef FLATPAK_ENABLE_P2P
+  str = g_key_file_get_string (keyfile, FLATPAK_REPO_GROUP, FLATPAK_REPO_COLLECTION_ID_KEY, NULL);
+  if (str != NULL)
+    opt_collection_id = str;
+#endif  /* FLATPAK_ENABLE_P2P */
+
   str = g_key_file_get_locale_string (keyfile, FLATPAK_REPO_GROUP,
                                       FLATPAK_REPO_TITLE_KEY, NULL, NULL);
   if (str != NULL)
@@ -309,6 +325,12 @@ flatpak_builtin_add_remote (int argc, char **argv,
   if (argc > 3)
     return usage_error (context, _("Too many arguments"), error);
 
+#ifdef FLATPAK_ENABLE_P2P
+  if (opt_collection_id != NULL &&
+      !ostree_validate_collection_id (opt_collection_id, &local_error))
+    return flatpak_fail (error, _("‘%s’ is not a valid collection ID: %s"), opt_collection_id, local_error->message);
+#endif  /* FLATPAK_ENABLE_P2P */
+
   remote_name = argv[1];
   location = argv[2];
 
diff --git a/app/flatpak-builtins-build-commit-from.c b/app/flatpak-builtins-build-commit-from.c
index 39c676b91..dde8c50e9 100644
--- a/app/flatpak-builtins-build-commit-from.c
+++ b/app/flatpak-builtins-build-commit-from.c
@@ -232,6 +232,7 @@ flatpak_builtin_build_commit_from (int argc, char **argv, GCancellable *cancella
       g_autofree char *commit_checksum = NULL;
       GVariantBuilder metadata_builder;
       gint j;
+      const char *dst_collection_id = NULL;
 
       if (!ostree_repo_resolve_rev (dst_repo, dst_ref, TRUE, &dst_parent, error))
         return FALSE;
@@ -273,9 +274,22 @@ flatpak_builtin_build_commit_from (int argc, char **argv, GCancellable *cancella
       if (opt_body)
         body = (const char *)opt_body;
 
+#ifdef FLATPAK_ENABLE_P2P
+      dst_collection_id = ostree_repo_get_collection_id (dst_repo);
+#endif  /* FLATPAK_ENABLE_P2P */
+
       /* Copy old metadata */
       g_variant_builder_init (&metadata_builder, G_VARIANT_TYPE ("a{sv}"));
+
+      /* Bindings. xa.ref is deprecated but added anyway for backwards compatibility.
+       * Add the bindings even if we are not built with P2P support, since other
+       * flatpak builds might be. */
+      g_variant_builder_add (&metadata_builder, "{sv}", "ostree.collection-binding",
+                             g_variant_new_string (dst_collection_id ? dst_collection_id : ""));
+      g_variant_builder_add (&metadata_builder, "{sv}", "ostree.ref-binding",
+                             g_variant_new_strv (&dst_ref, 1));
       g_variant_builder_add (&metadata_builder, "{sv}", "xa.ref", g_variant_new_string (dst_ref));
+
       /* Record the source commit. This is nice to have, but it also
          means the commit-from gets a different commit id, which
          avoids problems with e.g.  sharing .commitmeta files
@@ -289,7 +303,9 @@ flatpak_builtin_build_commit_from (int argc, char **argv, GCancellable *cancella
           const char *key = g_variant_get_string (keyv, NULL);
 
           if (strcmp (key, "xa.ref") == 0 ||
-              strcmp (key, "xa.from_commit") == 0)
+              strcmp (key, "xa.from_commit") == 0 ||
+              strcmp (key, "ostree.collection-binding") == 0 ||
+              strcmp (key, "ostree.ref-binding") == 0)
             continue;
 
           g_variant_builder_add_value (&metadata_builder, child);
@@ -330,7 +346,17 @@ flatpak_builtin_build_commit_from (int argc, char **argv, GCancellable *cancella
             }
         }
 
-      ostree_repo_transaction_set_ref (dst_repo, NULL, dst_ref, commit_checksum);
+#ifdef FLATPAK_ENABLE_P2P
+      if (dst_collection_id != NULL)
+        {
+          OstreeCollectionRef ref = { (char *) dst_collection_id, (char *) dst_ref };
+          ostree_repo_transaction_set_collection_ref (dst_repo, &ref, commit_checksum);
+        }
+      else
+#endif  /* FLATPAK_ENABLE_P2P */
+        {
+          ostree_repo_transaction_set_ref (dst_repo, NULL, dst_ref, commit_checksum);
+        }
     }
 
   if (!ostree_repo_commit_transaction (dst_repo, NULL, cancellable, error))
diff --git a/app/flatpak-builtins-build-export.c b/app/flatpak-builtins-build-export.c
index 788a074e3..fd0c85c08 100644
--- a/app/flatpak-builtins-build-export.c
+++ b/app/flatpak-builtins-build-export.c
@@ -45,6 +45,9 @@ static char *opt_gpg_homedir;
 static char *opt_files;
 static char *opt_metadata;
 static char *opt_timestamp = NULL;
+#ifdef FLATPAK_ENABLE_P2P
+static char *opt_collection_id = NULL;
+#endif  /* FLATPAK_ENABLE_P2P */
 
 static GOptionEntry options[] = {
   { "subject", 's', 0, G_OPTION_ARG_STRING, &opt_subject, N_("One line subject"), N_("SUBJECT") },
@@ -60,6 +63,9 @@ static GOptionEntry options[] = {
   { "include", 0, 0, G_OPTION_ARG_STRING_ARRAY, &opt_include, N_("Excluded files to include"), N_("PATTERN") },
   { "gpg-homedir", 0, 0, G_OPTION_ARG_STRING, &opt_gpg_homedir, N_("GPG Homedir to use when looking for keyrings"), N_("HOMEDIR") },
   { "timestamp", 0, 0, G_OPTION_ARG_STRING, &opt_timestamp, N_("Override the timestamp of the commit"), N_("ISO-8601-TIMESTAMP") },
+#ifdef FLATPAK_ENABLE_P2P
+  { "collection-id", 0, 0, G_OPTION_ARG_STRING, &opt_collection_id, N_("Collection ID"), "COLLECTION-ID" },
+#endif  /* FLATPAK_ENABLE_P2P */
 
   { NULL }
 };
@@ -651,6 +657,7 @@ flatpak_builtin_build_export (int argc, char **argv, GCancellable *cancellable,
   gboolean is_extension = FALSE;
   guint64 installed_size = 0,download_size = 0;
   GTimeVal ts;
+  const char *collection_id;
 
   context = g_option_context_new (_("LOCATION DIRECTORY [BRANCH] - Create a repository from a build directory"));
   g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
@@ -678,6 +685,15 @@ flatpak_builtin_build_export (int argc, char **argv, GCancellable *cancellable,
   else
     branch = "master";
 
+#ifdef FLATPAK_ENABLE_P2P
+  if (opt_collection_id != NULL &&
+      !ostree_validate_collection_id (opt_collection_id, &my_error))
+    {
+      flatpak_fail (error, _("‘%s’ is not a valid collection ID: %s"), opt_collection_id, my_error->message);
+      goto out;
+    }
+#endif  /* FLATPAK_ENABLE_P2P */
+
   if (!flatpak_is_valid_branch (branch, &my_error))
     {
       flatpak_fail (error, _("'%s' is not a valid branch name: %s"), branch, my_error->message);
@@ -772,13 +788,37 @@ flatpak_builtin_build_export (int argc, char **argv, GCancellable *cancellable,
 
       if (!ostree_repo_resolve_rev (repo, full_branch, TRUE, &parent, error))
         goto out;
+
+#ifdef FLATPAK_ENABLE_P2P
+      if (opt_collection_id != NULL &&
+          g_strcmp0 (ostree_repo_get_collection_id (repo), opt_collection_id) != 0)
+        {
+          flatpak_fail (error, "Specified collection ID ‘%s’ doesn’t match collection ID in repository configuration ‘%s’.",
+                        opt_collection_id, ostree_repo_get_collection_id (repo));
+          goto out;
+        }
+#endif  /* FLATPAK_ENABLE_P2P */
     }
   else
     {
+#ifdef FLATPAK_ENABLE_P2P
+      if (opt_collection_id != NULL &&
+          !ostree_repo_set_collection_id (repo, opt_collection_id, error))
+        goto out;
+#endif  /* FLATPAK_ENABLE_P2P */
       if (!ostree_repo_create (repo, OSTREE_REPO_MODE_ARCHIVE_Z2, cancellable, error))
         goto out;
     }
 
+  /* Get the canonical collection ID which we’ll use for the commit. This might
+   * be %NULL if the existing repo doesn’t have one and none was specified on
+   * the command line. */
+#ifdef FLATPAK_ENABLE_P2P
+  collection_id = ostree_repo_get_collection_id (repo);
+#else  /* if !FLATPAK_ENABLE_P2P */
+  collection_id = NULL;
+#endif  /* !FLATPAK_ENABLE_P2P */
+
   if (!ostree_repo_prepare_transaction (repo, NULL, cancellable, error))
     goto out;
 
@@ -836,7 +876,15 @@ flatpak_builtin_build_export (int argc, char **argv, GCancellable *cancellable,
   if (!flatpak_repo_collect_sizes (repo, root, &installed_size, &download_size, cancellable, error))
     goto out;
 
+  /* Binding information. xa.ref is deprecated in favour of the OSTree keys, but
+   * keep it around for backwards compatibility. Write the bindings even if
+   * we’re compiled without P2P support, since other flatpak builds might be. */
+  g_variant_dict_insert_value (&metadata_dict, "ostree.collection-binding",
+                               g_variant_new_string ((collection_id != NULL) ? collection_id : ""));
+  g_variant_dict_insert_value (&metadata_dict, "ostree.ref-binding",
+                               g_variant_new_strv ((const gchar * const *) &full_branch, 1));
   g_variant_dict_insert_value (&metadata_dict, "xa.ref", g_variant_new_string (full_branch));
+
   g_variant_dict_insert_value (&metadata_dict, "xa.metadata", g_variant_new_string (metadata_contents));
   g_variant_dict_insert_value (&metadata_dict, "xa.installed-size", g_variant_new_uint64 (GUINT64_TO_BE (installed_size)));
   g_variant_dict_insert_value (&metadata_dict, "xa.download-size", g_variant_new_uint64 (GUINT64_TO_BE (download_size)));
@@ -889,7 +937,17 @@ flatpak_builtin_build_export (int argc, char **argv, GCancellable *cancellable,
         }
     }
 
-  ostree_repo_transaction_set_ref (repo, NULL, full_branch, commit_checksum);
+#ifdef FLATPAK_ENABLE_P2P
+  if (collection_id != NULL)
+    {
+      OstreeCollectionRef ref = { (char *) collection_id, full_branch };
+      ostree_repo_transaction_set_collection_ref (repo, &ref, commit_checksum);
+    }
+  else
+#endif  /* FLATPAK_ENABLE_P2P */
+    {
+      ostree_repo_transaction_set_ref (repo, NULL, full_branch, commit_checksum);
+    }
 
   if (!ostree_repo_commit_transaction (repo, &stats, cancellable, error))
     goto out;
diff --git a/app/flatpak-builtins-repo-update.c b/app/flatpak-builtins-repo-update.c
index b920926bf..280958bb9 100644
--- a/app/flatpak-builtins-repo-update.c
+++ b/app/flatpak-builtins-repo-update.c
@@ -36,6 +36,7 @@
 static char *opt_title;
 static char *opt_redirect_url;
 static char *opt_default_branch;
+static char *opt_collection_id = NULL;
 static char **opt_gpg_import;
 static char *opt_generate_delta_from;
 static char *opt_generate_delta_to;
@@ -50,6 +51,9 @@ static GOptionEntry options[] = {
   { "redirect-url", 0, 0, G_OPTION_ARG_STRING, &opt_redirect_url, N_("Redirect this repo to a new URL"), N_("URL") },
   { "title", 0, 0, G_OPTION_ARG_STRING, &opt_title, N_("A nice name to use for this repository"), N_("TITLE") },
   { "default-branch", 0, 0, G_OPTION_ARG_STRING, &opt_default_branch, N_("Default branch to use for this repository"), N_("BRANCH") },
+#ifdef FLATPAK_ENABLE_P2P
+  { "collection-id", 0, 0, G_OPTION_ARG_STRING, &opt_collection_id, N_("Collection ID"), N_("COLLECTION-ID") },
+#endif  /* FLATPAK_ENABLE_P2P */
   { "gpg-import", 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &opt_gpg_import, N_("Import new default GPG public key from FILE"), N_("FILE") },
   { "gpg-sign", 0, 0, G_OPTION_ARG_STRING_ARRAY, &opt_gpg_key_ids, N_("GPG Key ID to sign the summary with"), N_("KEY-ID") },
   { "gpg-homedir", 0, 0, G_OPTION_ARG_STRING, &opt_gpg_homedir, N_("GPG Homedir to use when looking for keyrings"), N_("HOMEDIR") },
@@ -435,6 +439,10 @@ flatpak_builtin_build_update_repo (int argc, char **argv,
       !flatpak_repo_set_default_branch (repo, opt_default_branch[0] ? opt_default_branch : NULL, error))
     return FALSE;
 
+  if (opt_collection_id &&
+      !flatpak_repo_set_collection_id (repo, opt_collection_id[0] ? opt_collection_id : NULL, error))
+    return FALSE;
+
   if (opt_gpg_import)
     {
       g_autoptr(GBytes) gpg_data = flatpak_load_gpg_keys (opt_gpg_import, cancellable, error);
diff --git a/app/flatpak-builtins-repo.c b/app/flatpak-builtins-repo.c
index 54de28f7e..f4691e274 100644
--- a/app/flatpak-builtins-repo.c
+++ b/app/flatpak-builtins-repo.c
@@ -38,6 +38,7 @@ print_info (GVariant *meta)
 {
   g_autoptr(GVariant) cache = NULL;
   const char *title;
+  const char *collection_id;
   const char *default_branch;
   const char *redirect_url;
   g_autoptr(GVariant) gpg_keys = NULL;
@@ -45,6 +46,9 @@ print_info (GVariant *meta)
   if (g_variant_lookup (meta, "xa.title", "&s", &title))
     g_print ("Title: %s\n", title);
 
+  if (g_variant_lookup (meta, "collection-id", "&s", &collection_id))
+    g_print ("Collection ID: %s\n", collection_id);
+
   if (g_variant_lookup (meta, "xa.default-branch", "&s", &default_branch))
     g_print ("Default branch: %s\n", default_branch);
 
diff --git a/doc/flatpak-build-commit-from.xml b/doc/flatpak-build-commit-from.xml
index 0ddf223e2..52f39b0e0 100644
--- a/doc/flatpak-build-commit-from.xml
+++ b/doc/flatpak-build-commit-from.xml
@@ -46,6 +46,11 @@
             contents (and most of the metadata) taken from another
             branch, either from another repo, or from another branch in
             the same repository.
+            <!-- FIXME: Uncomment this when enable-p2p is enabled unconditionally.
+            The collection ID set on
+            <arg choice="plain">DST-REPO</arg> (if set) will be used for the
+            newly created commits.
+            -->
         </para>
         <para>
             This command is very useful when you want to maintain a branch
diff --git a/doc/flatpak-build-export.xml b/doc/flatpak-build-export.xml
index 2d84cae9b..ec3d077fc 100644
--- a/doc/flatpak-build-export.xml
+++ b/doc/flatpak-build-export.xml
@@ -63,6 +63,16 @@
             subdirectories and the <filename>metadata</filename> file are included
             in the commit, anything else is ignored.
         </para>
+        <!-- FIXME: Uncomment this when enable-p2p is enabled unconditionally.
+        <para>
+            When exporting a flatpak to be published to the internet,
+            <option>-FIXME-collection-id=COLLECTION-ID</option> should be specified
+            as a globally unique reverse DNS value to identify the collection of
+            flatpaks this will be added to. Setting a globally unique collection
+            ID allows the apps in the repository to be shared over peer to peer
+            systems without needing further configuration.
+        </para>
+        -->
         <para>
             The build-update-repo command should be used to update repository
             metadata whenever application builds are added to a repository.
@@ -102,6 +112,21 @@
                 </para></listitem>
             </varlistentry>
 
+            <!-- FIXME: Uncomment this when enable-p2p is enabled unconditionally.
+            <varlistentry>
+                <term><option>-FIXME-collection-id=COLLECTION-ID</option></term>
+
+                <listitem><para>
+                    Set as the collection ID of the repository. Setting a globally
+                    unique collection ID allows the apps in the repository to be shared over
+                    peer to peer systems without needing further configuration.
+                    If exporting to an existing repository, the collection ID
+                    must match the existing configured collection ID for that
+                    repository.
+                </para></listitem>
+            </varlistentry>
+            -->
+
             <varlistentry>
                 <term><option>--arch=ARCH</option></term>
 
diff --git a/doc/flatpak-build-update-repo.xml b/doc/flatpak-build-update-repo.xml
index b1369be0a..953fd0e38 100644
--- a/doc/flatpak-build-update-repo.xml
+++ b/doc/flatpak-build-update-repo.xml
@@ -102,6 +102,21 @@
                 </para></listitem>
             </varlistentry>
 
+            <!-- FIXME: Uncomment this when enable-p2p is enabled unconditionally.
+            <varlistentry>
+                <term><option>-FIXME-collection-id=COLLECTION-ID</option></term>
+
+                <listitem><para>
+                    The globally unique identifier of the remote repository, to
+                    allow mirrors to be grouped. This must be set to a globally
+                    unique reverse DNS string if the repository is to be made
+                    publicly available. If a collection ID is already set on an
+                    existing repository, this will update it. If not specified,
+                    the existing collection ID will be left unchanged.
+                </para></listitem>
+            </varlistentry>
+            -->
+
             <varlistentry>
                 <term><option>--gpg-sign=KEYID</option></term>
 
diff --git a/doc/flatpak-remote-modify.xml b/doc/flatpak-remote-modify.xml
index f0c70bddd..3f5b58bc6 100644
--- a/doc/flatpak-remote-modify.xml
+++ b/doc/flatpak-remote-modify.xml
@@ -187,6 +187,19 @@
                 </para></listitem>
             </varlistentry>
 
+            <!-- FIXME: Uncomment this when enable-p2p is enabled unconditionally.
+            <varlistentry>
+                <term><option>-FIXME-collection-id=COLLECTION-ID</option></term>
+
+                <listitem><para>
+                    The globally unique identifier of the remote repository, to
+                    allow mirrors to be grouped. This must only be set to the
+                    collection ID provided by the remote, and must not be set if the
+                    remote does not provide an collection ID.
+                </para></listitem>
+            </varlistentry>
+            -->
+
             <varlistentry>
                 <term><option>--url=URL</option></term>
 
diff --git a/doc/flatpak-remote.xml b/doc/flatpak-remote.xml
index 1afa77ffe..e263b8e13 100644
--- a/doc/flatpak-remote.xml
+++ b/doc/flatpak-remote.xml
@@ -80,6 +80,12 @@
                     <term><option>gpg-verify-summary</option> (boolean)</term>
                     <listitem><para>Whether to use GPG verification for the summary of this remote.</para></listitem>
                 </varlistentry>
+                <!-- FIXME: Uncomment this when enable-p2p is enabled unconditionally.
+                <varlistentry>
+                    <term><option>collection-id</option> (string)</term>
+                    <listitem><para>The globally unique identifier for the upstream collection repository, to allow mirrors to be grouped.</para></listitem>
+                </varlistentry>
+                -->
             </variablelist>
             <para>
                 All flatpak-specific keys have a xa. prefix: