Meshtastic-Android/docs/kmp-status.md

KMP Migration Status

Last updated: 2026-03-13

Single source of truth for Kotlin Multiplatform migration progress. For the forward-looking roadmap, see roadmap.md. For completed decision records, see decisions/.

Summary

Meshtastic-Android has completed its Android-first structural KMP migration across core logic and feature modules, with full JVM cross-compilation validated in CI. The desktop target has a working Navigation 3 shell, TCP transport with full mesh handshake, and multiple features wired with real screens.

Modules that share JVM-specific code between Android and desktop now standardize on the meshtastic.kmp.jvm.android convention plugin, which creates jvmAndroidMain via Kotlin's hierarchy template API instead of manual dependsOn(...) source-set wiring.

Module Inventory

Core Modules (20 total)

Module	KMP?	JVM target?	Notes
core:proto	✅	✅	Protobuf definitions
core:common	✅	✅	Utilities, jvmAndroidMain source set
core:model	✅	✅	Domain models, jvmAndroidMain source set
core:repository	✅	✅	Domain interfaces
core:di	✅	✅	Dispatchers, qualifiers
core:navigation	✅	✅	Shared Navigation 3 routes
core:resources	✅	✅	Compose Multiplatform resources
core:datastore	✅	✅	Multiplatform DataStore
core:database	✅	✅	Room KMP
core:domain	✅	✅	UseCases
core:prefs	✅	✅	Preferences layer
core:network	✅	✅	Ktor, StreamFrameCodec, TcpTransport
core:data	✅	✅	Data orchestration
core:ble	✅	✅	BLE abstractions in commonMain; Nordic in androidMain
core:nfc	✅	✅	NFC contract in commonMain; hardware in androidMain
core:service	✅	✅	Service layer; Android bindings in androidMain
core:ui	✅	✅	Shared Compose UI, jvmAndroidMain + jvmMain actuals
core:testing	✅	✅	Shared test doubles, fakes, and utilities for commonTest
core:api	❌	—	Android-only (AIDL). Intentional.
core:barcode	❌	—	Android-only (CameraX). Flavor split minimised to decoder factory only (ML Kit / ZXing). Shared contract in core:ui.

18/20 core modules are KMP with JVM targets. The 2 Android-only modules are intentionally platform-specific, with shared contracts already abstracted into core:ui/commonMain.

Feature Modules (7 total — all KMP with JVM)

Module	UI in commonMain?	Desktop wired?
feature:settings	✅	✅ ~35 real screens; shared ChannelViewModel
feature:node	✅	✅ Adaptive list-detail; shared NodeContextMenu
feature:messaging	✅	✅ Adaptive contacts + messages; 17 shared files in commonMain (ViewModels, MessageBubble, MessageItem, QuickChat, Reactions, DeliveryInfo, actions, events)
feature:connections	✅	✅ Shared ConnectionsScreen with dynamic transport detection
feature:intro	✅	—
feature:map	✅	Placeholder; shared NodeMapViewModel
feature:firmware	—	Placeholder; DFU is Android-only

Desktop Module

Working Compose Desktop application with:

• Navigation 3 shell (NavigationRail + NavDisplay) using shared routes
• Full Koin DI graph (stubs + real implementations)
• TCP transport with auto-reconnect and full want_config handshake
• Adaptive list-detail screens for nodes and contacts
• Dynamic Connections screen with automatic discovery of platform-supported transports (TCP)
• Desktop language picker backed by UiPreferencesDataSource.locale, with immediate Compose Multiplatform resource updates
• Navigation-preserving locale switching via Main.kt staticCompositionLocalOf recomposition instead of recreating the Nav3 backstack
• Node detail metrics screens (Device, Environment, Signal, Power, Pax) wired with shared KMP + Vico charts
• 7 desktop-specific screens (Settings, Device, Position, Network, Security, ExternalNotification, Debug)
• Native release pipeline generating .dmg (macOS), .msi (Windows), and .deb (Linux) installers in CI

Scorecard

Area	Score	Notes
Shared business/data logic	9/10	All core layers shared; RadioTransport interface unified
Shared feature/UI logic	8.5/10	All 7 KMP; feature:connections unified with dynamic transport detection
Android decoupling	8/10	No known java.* calls in commonMain; app module extraction in progress
Multi-target readiness	8/10	Full JVM; release-ready desktop; iOS not declared
CI confidence	9/10	25 modules validated (including feature:connections); native release installers automated
DI portability	8/10	Koin annotations in commonMain; supportedDeviceTypes injected per platform
Test maturity	8/10	131 commonTest + 89 platform-specific = 219 tests across all 7 features; core:testing established

See decisions/architecture-review-2026-03.md for the full gap analysis.

Completion Estimates

Lens	%
Android-first structural KMP	~98%
Shared business logic	~95%
Shared feature/UI	~90%
True multi-target readiness	~75%
"Add iOS without surprises"	~65%

Proposed Next Steps for KMP Migration

Based on the latest codebase investigation, the following steps are proposed to complete the multi-target and iOS-readiness migrations:

1. Extract remaining App-Only ViewModels: Migrate the 5 remaining Android*ViewModels by isolating their Android-specific dependencies (e.g., android.net.Uri for file I/O, Location permissions) behind expect/actual or injected interface abstractions.
2. Wire Desktop Features: Complete desktop UI wiring for feature:intro and implement a shared fallback for feature:map (which is currently a placeholder on desktop).
3. Decouple Firmware DFU: feature:firmware relies on Android-only DFU libraries. Evaluate wrapping this in a shared KMP interface or extracting it into a separate plugin to allow the core feature:firmware module to be fully utilized on desktop/iOS.
4. Prepare for iOS Target: Set up an initial skeleton Xcode project to start validating commonMain compilation on Kotlin/Native (iOS).

Key Architecture Decisions

Decision	Status	Details
Navigation 3 parity model (shared TopLevelDestination + platform adapters)	✅ Done	Both shells use shared enum + parity tests. See decisions/navigation3-parity-2026-03.md
Hilt → Koin	✅ Done	See decisions/koin-migration.md
BLE abstraction (Nordic Hybrid)	✅ Done	See decisions/ble-strategy.md
Material 3 Adaptive (JetBrains)	✅ Done	Version 1.3.0-alpha06 aligned with CMP 1.11.0-alpha04
JetBrains lifecycle/nav3 alias alignment	✅ Done	All forked deps use jetbrains-* prefix in version catalog; core:data commonMain uses JetBrains lifecycle runtime
Expect/actual consolidation	✅ Done	7 pairs eliminated; 15+ genuinely platform-specific retained
Transport deduplication	✅ Done	StreamFrameCodec + TcpTransport shared in core:network
Transport UI Unification	✅ Done	RadioInterfaceService provides dynamic transport capability to shared UI
Emoji picker unification	✅ Done	Single commonMain implementation replacing 3 platform variants

Navigation Parity Note

• Desktop and Android both use the shared TopLevelDestination enum from core:navigation/commonMain — no separate DesktopDestination remains.
• Both shells iterate TopLevelDestination.entries with shared icon mapping from core:ui (TopLevelDestinationExt.icon).
• Desktop locale changes now trigger a full subtree recomposition from Main.kt without resetting the shared Navigation 3 backstack, so translated labels update in place.
• Firmware remains available as an in-flow route instead of a top-level destination, matching Android information architecture.
• Parity tests exist in core:navigation/commonTest (NavigationParityTest) and desktop/test (DesktopTopLevelDestinationParityTest).
• Remaining parity work is documented in decisions/navigation3-parity-2026-03.md: serializer registration validation and platform exception tracking.

Remaining App-Only ViewModels

Only ViewModels with genuine Android-specific logic retain wrappers:

ViewModel	Android-Specific Reason
AndroidSettingsViewModel	File I/O via android.net.Uri
AndroidRadioConfigViewModel	Location permissions, file I/O
AndroidDebugViewModel	Locale-aware hex formatting
AndroidMetricsViewModel	CSV export via android.net.Uri
UIViewModel	Deep links via android.net.Uri, IMeshService

Extracted to shared commonMain (no longer app-only):

• ChannelViewModel → feature:settings/commonMain
• NodeMapViewModel → feature:map/commonMain

Prerelease Dependencies

Dependency	Version	Why
Compose Multiplatform	1.11.0-alpha04	Required for JetBrains Adaptive 1.3.0-alpha06
Koin	4.2.0-RC2	Nav3 + K2 compiler plugin support
JetBrains Lifecycle	2.10.0-beta01	Multiplatform ViewModel/lifecycle
JetBrains Navigation 3	1.1.0-alpha04	Multiplatform navigation
Nordic BLE	2.0.0-alpha16	Behind abstraction boundary

Policy: Stable by default. RC when it unlocks KMP functionality. Alpha only behind hard abstraction seams. Do not downgrade CMP or Koin — they enable critical KMP features.

References

• Roadmap: docs/roadmap.md
• Agent guide: AGENTS.md
• Playbooks: docs/agent-playbooks/
• Decision records: docs/decisions/