- KMP AGP 9.0 Migration
- Android Gradle Plugin 9.0 makes the Android application and library plugins incompatible
- with the Kotlin Multiplatform plugin in the same module. This skill guides you through the
- migration.
- Step 0: Analyze the Project
- Before making any changes, understand the project structure:
- Read
- settings.gradle.kts
- (or
- .gradle
- ) to find all modules
- For each module, read its
- build.gradle.kts
- to identify which plugins are applied
- Check if the project uses a Gradle version catalog (
- gradle/libs.versions.toml
- ). If it exists,
- read it for current AGP/Gradle/Kotlin versions. If not, find versions directly in
- build.gradle.kts
- files (typically in the root
- buildscript {}
- or
- plugins {}
- block).
- Adapt all examples in this
- guide accordingly
- — version catalog examples use
- alias(libs.plugins.xxx)
- while direct usage
- uses
- id("plugin.id") version "x.y.z"
- Read
- gradle/wrapper/gradle-wrapper.properties
- for the Gradle version
- Check
- gradle.properties
- for any existing workarounds (
- android.enableLegacyVariantApi
- )
- Check for
- org.jetbrains.kotlin.android
- plugin usage — AGP 9.0 has built-in Kotlin and this plugin must be removed
- Check for
- org.jetbrains.kotlin.kapt
- plugin usage — incompatible with built-in Kotlin, must migrate to KSP or
- com.android.legacy-kapt
- Check for third-party plugins that may be incompatible with AGP 9.0 (see "Plugin Compatibility" section below)
- If Bash is available, run
- scripts/analyze-project.sh
- from this skill's directory to get a structured summary.
- Classify Each Module
- For each module, determine its type:
- Current plugins
- Migration path
- kotlin.multiplatform
- +
- com.android.library
- Path A
- — Library plugin swap
- kotlin.multiplatform
- +
- com.android.application
- Path B
- — Mandatory Android split
- kotlin.multiplatform
- with multiple platform entry points in one module
- Path C
- — Full restructure (recommended)
- com.android.application
- or
- com.android.library
- (no KMP)
- See "Pure Android Tips" below
- Determine Scope
- Path B is mandatory
- for any module combining KMP + Android application plugin
- Path C is recommended
- when the project has a monolithic
- composeApp
- (or similar) module
- containing entry points for multiple platforms (Android, Desktop, Web). This aligns with the
- new JetBrains default project structure where each platform gets its own app module.
- Ask the user
- whether they want Path B only (minimum required) or Path C (recommended full restructure)
- Path A: Library Module Migration
- Use this when a module applies
- kotlin.multiplatform
- +
- com.android.library
- .
- See
- references/MIGRATION-LIBRARY.md
- for full before/after code.
- Summary:
- Replace plugin
- :
- com.android.library
- →
- com.android.kotlin.multiplatform.library
- Remove
- org.jetbrains.kotlin.android
- plugin if present (AGP 9.0 has built-in Kotlin support)
- Migrate DSL
-
- Move config from top-level
- android {}
- block into
- kotlin { android {} }
- :
- kotlin
- {
- android
- {
- namespace
- =
- "com.example.lib"
- compileSdk
- =
- 35
- minSdk
- =
- 24
- }
- }
- Rename source directories
- (only if the module uses classic Android layout instead of KMP layout):
- src/main
- →
- src/androidMain
- src/test
- →
- src/androidHostTest
- src/androidTest
- →
- src/androidDeviceTest
- If the module already uses
- src/androidMain/
- , no directory renames are needed
- Move dependencies
- from top-level
- dependencies {}
- into
- sourceSets
- :
- kotlin
- {
- sourceSets
- {
- androidMain
- .
- dependencies
- {
- implementation
- (
- "androidx.appcompat:appcompat:1.7.0"
- )
- }
- }
- }
- Enable resources
- explicitly if the module uses Android or Compose Multiplatform resources:
- kotlin
- {
- android
- {
- androidResources
- {
- enable
- =
- true
- }
- }
- }
- Enable Java
- compilation if module has
- .java
- source files:
- kotlin
- {
- android
- {
- withJava
- (
- )
- }
- }
- Enable tests
- explicitly if the module has unit or instrumented tests:
- kotlin
- {
- android
- {
- withHostTest
- {
- isIncludeAndroidResources
- =
- true
- }
- withDeviceTest
- {
- instrumentationRunner
- =
- "androidx.test.runner.AndroidJUnitRunner"
- }
- }
- }
- Update Compose tooling dependency
- :
- // Old:
- debugImplementation
- (
- libs
- .
- androidx
- .
- compose
- .
- ui
- .
- tooling
- )
- // New:
- androidRuntimeClasspath
- (
- libs
- .
- androidx
- .
- compose
- .
- ui
- .
- tooling
- )
- Publish consumer ProGuard rules
- explicitly if applicable:
- kotlin
- {
- android
- {
- consumerProguardFiles
- .
- add
- (
- file
- (
- "consumer-rules.pro"
- )
- )
- }
- }
- Resolve Sub-dependency Variants (Product Flavors / Build Types)
- :
- Because the new KMP Android library plugin enforces a single-variant architecture, it does not natively understand how to resolve dependencies that publish multiple variants (like
- debug
- /
- release
- build types, or product flavors like
- free
- /
- paid
- ). Configure fallback behaviors using
- localDependencySelection
- :
- kotlin
- {
- android
- {
- localDependencySelection
- {
- // Determine which build type to consume from Android library dependencies, in order of preference
- selectBuildTypeFrom
- .
- set
- (
- listOf
- (
- "debug"
- ,
- "release"
- )
- )
- // If the dependency has a 'tier' dimension, select the 'free' flavor
- productFlavorDimension
- (
- "tier"
- )
- {
- selectFrom
- .
- set
- (
- listOf
- (
- "free"
- )
- )
- }
- }
- }
- }
- Path B: Android App + Shared Module Split
- Use this when a module applies
- kotlin.multiplatform
- +
- com.android.application
- . This is
- mandatory
- for AGP 9.0 compatibility.
- See
- references/MIGRATION-APP-SPLIT.md
- for full guide.
- Summary:
- Create
- androidApp
- module
- with its own
- build.gradle.kts
- :
- plugins
- {
- alias
- (
- libs
- .
- plugins
- .
- androidApplication
- )
- // Do NOT apply kotlin-android — AGP 9.0 includes Kotlin support
- alias
- (
- libs
- .
- plugins
- .
- composeMultiplatform
- )
- // if using Compose
- alias
- (
- libs
- .
- plugins
- .
- composeCompiler
- )
- // if using Compose
- }
- android
- {
- namespace
- =
- "com.example.app"
- compileSdk
- =
- 35
- defaultConfig
- {
- applicationId
- =
- "com.example.app"
- minSdk
- =
- 24
- targetSdk
- =
- 35
- versionCode
- =
- 1
- versionName
- =
- "1.0"
- }
- buildFeatures
- {
- compose
- =
- true
- }
- }
- dependencies
- {
- implementation
- (
- projects
- .
- shared
- )
- // or whatever the shared module is named
- implementation
- (
- libs
- .
- androidx
- .
- activity
- .
- compose
- )
- }
- Move Android entry point code
- from
- src/androidMain/
- to
- androidApp/src/main/
- :
- MainActivity.kt
- (and any other Activities/Fragments)
- AndroidManifest.xml
- (app-level manifest with
- and launcher
- ) — verify
- android:name
- on
- uses the fully qualified class name in its new location
- Android Application class if present
- App-level resources (launcher icons, theme, etc.)
- Add to
- settings.gradle.kts
- :
- include(":androidApp")
- Add to root
- build.gradle.kts
-
- plugin declarations with
- apply false
- Convert original module
- from application to library using Path A steps
- Ensure different namespaces
-
- app module and library module must have distinct namespaces
- Remove from shared module
- :
- applicationId
- ,
- targetSdk
- ,
- versionCode
- ,
- versionName
- Update IDE run configurations
-
- change the module from the old module to
- androidApp
- Path C: Full Restructure (Recommended)
- Use this when the project has a monolithic module (typically
- composeApp
- ) containing entry
- points for multiple platforms. This is optional but aligns with the new JetBrains default.
- See
- references/MIGRATION-FULL-RESTRUCTURE.md
- for full guide.
- Target Structure
- project/
- ├── shared/ ← KMP library (was composeApp), pure shared code
- ├── androidApp/ ← Android entry point only
- ├── desktopApp/ ← Desktop entry point only (if desktop target exists)
- ├── webApp/ ← Wasm/JS entry point only (if web target exists)
- ├── iosApp/ ← iOS Xcode project (usually already separate)
- └── ...
- Steps
- Apply Path B first
- — extract
- androidApp
- (mandatory for AGP 9.0)
- Extract
- desktopApp
- (if desktop target exists):
- Create module with
- org.jetbrains.compose
- and
- application {}
- plugin
- Move
- main()
- function from
- desktopMain
- to
- desktopApp/src/main/kotlin/
- Move
- compose.desktop { application { ... } }
- config to
- desktopApp/build.gradle.kts
- Add dependency on
- shared
- module
- Extract
- webApp
- (if wasmJs/js target exists):
- Create module with appropriate Kotlin/JS or Kotlin/Wasm configuration
- Move web entry point from
- wasmJsMain
- /
- jsMain
- to
- webApp/src/wasmJsMain/kotlin/
- Move browser/distribution config to
- webApp/build.gradle.kts
- Add dependency on
- shared
- module
- iOS
- — typically already in a separate
- iosApp
- directory. Verify:
- Framework export config (
- binaries.framework
- ) stays in
- shared
- module
- Xcode project references the correct framework path
- Rename module
- from
- composeApp
- to
- shared
- :
- Rename directory
- Update
- settings.gradle.kts
- include
- Update all dependency references across modules
- Clean up shared module
- remove all platform entry point code and app-specific config that was moved to the platform app modules Variant: Native UI If some platforms use native UI (e.g., SwiftUI for iOS), split shared into: sharedLogic — business logic consumed by ALL platforms sharedUI — Compose Multiplatform UI consumed only by platforms using shared UI Variant: Server If the project includes a server target: Add server module at the root Move all client modules under an app/ directory Add core module for code shared between server and client (models, validation) Version Updates These are required regardless of migration path: Gradle wrapper — update to 9.1.0+:
gradle/wrapper/gradle-wrapper.properties
distributionUrl
https\://services.gradle.org/distributions/gradle-9.1.0-bin.zip AGP version — update to 9.0.0+ and add the KMP library plugin. With version catalog ( gradle/libs.versions.toml ): [ versions ] agp = "9.0.1" [ plugins ] android-kotlin-multiplatform-library = { id = "com.android.kotlin.multiplatform.library" , version.ref = "agp" } Without version catalog — update com.android.* plugin versions and add in root build.gradle.kts : plugins { id ( "com.android.application" ) version "9.0.1" apply false id ( "com.android.kotlin.multiplatform.library" ) version "9.0.1" apply false } JDK — ensure JDK 17+ is used (required by AGP 9.0) SDK Build Tools — update to 36.0.0: Install via SDK Manager or configure in android { buildToolsVersion = "36.0.0" } Review gradle.properties — remove error-causing properties and review changed defaults (see "Gradle Properties Default Changes" section) Built-in Kotlin Migration AGP 9.0 enables built-in Kotlin support by default for all com.android.application and com.android.library modules. The org.jetbrains.kotlin.android plugin is no longer needed and will conflict if applied. Important: Built-in Kotlin does NOT replace KMP support. KMP library modules still need org.jetbrains.kotlin.multiplatform + com.android.kotlin.multiplatform.library . Step 1: Remove kotlin-android Plugin Remove from all module-level and root-level build files: // Remove from module build.gradle.kts plugins { // REMOVE: alias(libs.plugins.kotlin.android) // REMOVE: id("org.jetbrains.kotlin.android") } // Remove from root build.gradle.kts plugins { // REMOVE: alias(libs.plugins.kotlin.android) apply false } Remove from version catalog ( gradle/libs.versions.toml ): [ plugins ]
REMOVE: kotlin-android =
Step 2: Migrate kapt to KSP or legacy-kapt The org.jetbrains.kotlin.kapt plugin is incompatible with built-in Kotlin. Preferred: Migrate to KSP — see the KSP migration guide for each annotation processor. Fallback: Use com.android.legacy-kapt (same version as AGP):
gradle/libs.versions.toml
[ plugins ] legacy-kapt = { id = "com.android.legacy-kapt" , version.ref = "agp" } // Module build.gradle.kts — replace kotlin-kapt with legacy-kapt plugins { // REMOVE: alias(libs.plugins.kotlin.kapt) alias ( libs . plugins . legacy . kapt ) } Step 3: Migrate kotlinOptions to compilerOptions For pure Android modules (non-KMP), migrate android.kotlinOptions {} to the top-level kotlin.compilerOptions {} : // Old android { kotlinOptions { jvmTarget = "11" languageVersion = "2.0" freeCompilerArgs += listOf ( "-Xopt-in=kotlin.RequiresOptIn" ) } } // New kotlin { compilerOptions { jvmTarget . set ( org . jetbrains . kotlin . gradle . dsl . JvmTarget . JVM_11 ) languageVersion . set ( org . jetbrains . kotlin . gradle . dsl . KotlinVersion . KOTLIN_2_0 ) optIn . add ( "kotlin.RequiresOptIn" ) } } Note: With built-in Kotlin, jvmTarget defaults to android.compileOptions.targetCompatibility , so it may be optional if you already set compileOptions . Step 4: Migrate kotlin.sourceSets to android.sourceSets With built-in Kotlin, only android.sourceSets {} with the kotlin set is supported: // NOT SUPPORTED with built-in Kotlin: kotlin . sourceSets . named ( "main" ) { kotlin . srcDir ( "additionalSourceDirectory/kotlin" ) } // Correct: android . sourceSets . named ( "main" ) { kotlin . directories += "additionalSourceDirectory/kotlin" } For generated sources, use the Variant API: androidComponents . onVariants { variant -> variant . sources . kotlin !! . addStaticSourceDirectory ( "additionalSourceDirectory/kotlin" ) } Per-Module Migration Strategy For large projects, migrate module-by-module: Disable globally: android.builtInKotlin=false in gradle.properties Enable per migrated module by applying the opt-in plugin: plugins { id ( "com.android.built-in-kotlin" ) version "AGP_VERSION" } Follow Steps 1-4 for that module Once all modules are migrated, remove android.builtInKotlin=false and all com.android.built-in-kotlin plugins Optional: Disable Kotlin for Non-Kotlin Modules For modules that contain no Kotlin sources , disable built-in Kotlin to save build time: android { enableKotlin = false } Opt-Out (Temporary) If blocked by plugin incompatibilities, opt out temporarily:
gradle.properties
android.builtInKotlin
false android.newDsl = false # also required if using new DSL opt-out Warning: Ask the user if they want to opt out, and if so, remind them this is a temporary measure. Plugin Compatibility See references/PLUGIN-COMPATIBILITY.md for the full compatibility table with known compatible versions, opt-out flag workarounds, and broken plugins. Before migrating , inventory all plugins in the project and check each against that table. If any plugin is broken without workaround, inform the user. If plugins need opt-out flags, add them to gradle.properties and note them as temporary workarounds. Gradle Properties Default Changes AGP 9.0 changes the defaults for many Gradle properties. Check gradle.properties for any explicitly set values that may now conflict. Key changes: Property Old Default New Default Action android.uniquePackageNames false true Ensure each library has a unique namespace android.enableAppCompileTimeRClass false true Refactor switch on R fields to if/else android.defaults.buildfeatures.resvalues true false Enable resValues = true where needed android.defaults.buildfeatures.shaders true false Enable shaders where needed android.r8.optimizedResourceShrinking false true Review R8 keep rules android.r8.strictFullModeForKeepRules false true Update keep rules to be explicit android.proguard.failOnMissingFiles false true Remove invalid ProGuard file references android.r8.proguardAndroidTxt.disallowed false true Use proguard-android-optimize.txt only android.r8.globalOptionsInConsumerRules.disallowed false true Remove global options from library consumer rules android.sourceset.disallowProvider false true Use Sources API on androidComponents android.sdk.defaultTargetSdkToCompileSdkIfUnset false true Specify targetSdk explicitly android.onlyEnableUnitTestForTheTestedBuildType false true Only if testing non-default build types Check for and remove properties that now cause errors: android.r8.integratedResourceShrinking — removed, always on android.enableNewResourceShrinker.preciseShrinking — removed, always on Pure Android Tips For non-KMP Android modules upgrading to AGP 9.0, follow the "Built-in Kotlin Migration" steps above, then review the "Gradle Properties Default Changes" table. Additional changes: Review new DSL interfaces — BaseExtension is removed; use CommonExtension or specific extension types Java default changed from Java 8 to Java 11 — ensure compileOptions reflects this Verification After migration, verify with the checklist . Key checks: ./gradlew build succeeds with no errors All platform targets build successfully (Android, iOS via xcodebuild , Desktop, JS/Wasm) ./gradlew :shared:allTests and Android unit tests pass No com.android.library or com.android.application in KMP modules No org.jetbrains.kotlin.android in AGP 9.0 modules Source sets use correct names ( androidMain , androidHostTest , androidDeviceTest ) No deprecation warnings about variant API or DSL Common Issues See references/KNOWN-ISSUES.md for details. Key gotchas: KMP Library Plugin Issues BuildConfig unavailable in library modules — use DI/ AppConfiguration interface, or use BuildKonfig or gradle-buildconfig-plugin for compile-time constants No build variants — single variant architecture; compile-time constants can use BuildKonfig/gradle-buildconfig-plugin flavors, but variant-specific dependencies/resources/signing must move to app module NDK/JNI unsupported in new plugin — extract to separate com.android.library module Compose resources crash without androidResources { enable = true } Consumer ProGuard rules silently dropped if not migrated to consumerProguardFiles.add(file(...)) in new DSL KSP requires version 2.3.1+ for AGP 9.0 compatibility AGP 9.0 General Issues BaseExtension removed — convention plugins using old DSL types need rewriting to use CommonExtension Variant APIs removed — applicationVariants , libraryVariants , variantFilter replaced by androidComponents Convention plugins need refactoring — old android {} extension helpers are obsolete Reference Files DSL Reference — side-by-side old→new DSL mapping Version Matrix — AGP/Gradle/KGP/Compose/IDE compatibility Plugin Compatibility — third-party plugin status and workarounds