Migration Guide — Android (5.x to 6.x)

Version 6.x is a major release focused on modern Android development with Jetpack Compose and Kotlin Coroutines.

Toolchain Requirements

Upgrade your project to meet the minimum requirements:

Tool	Required version
Android Gradle Plugin	9.1
Gradle	9.4
Kotlin	2.4
JDK	17
compileSdk / targetSdk	36
minSdk	23

Remove multidex (not needed with minSdk ≥ 21) and remove Jetifier (android.enableJetifier) from gradle.properties — Arkitekt is AndroidX-only.

Hilt + Kotlin 2.4

Hilt currently bundles an older kotlin-metadata-jvm that may fail to parse Kotlin 2.4 metadata (google/dagger#5001). If you hit a metadata parsing error during the KSP/Hilt build, add the matching version as a KSP dependency so the highest version on the processor classpath wins:

dependencies {
    ksp("org.jetbrains.kotlin:kotlin-metadata-jvm:2.4.0")
}

This is a temporary workaround until Hilt updates its bundled version.

Removed Modules

Module	Replacement
rx-usecases, rx-usecases-test	cr-usecases (Coroutines)
dagger	Dagger-Hilt (@HiltViewModel, @AndroidEntryPoint)
bindingadapters	Jetpack Compose
example-minimal, example-hilt	Consolidated example module

Removed Classes

ViewModel Base Classes

Removed	Replacement
BaseViewModel (from core)	BaseCoreViewModel (core) or BaseViewModel (compose)
BaseCrViewModel (from cr-usecases)	BaseViewModel (compose)

Fragment / Activity Base Classes

Removed	Replacement
ViewModelActivity, BindingViewModelActivity	ComponentActivity with @AndroidEntryPoint
ViewModelFragment, BindingViewModelFragment	Compose navigation
ViewModelBottomSheetDialogFragment, BindingViewModelBottomSheetDialogFragment	Compose bottom sheets
ViewModelDialogFragment, BindingViewModelDialogFragment	Compose dialogs

Dagger Classes

Removed	Replacement
BaseViewModelFactory, BaseSavedStateViewModelFactory	@HiltViewModel with hiltViewModel()
BaseDaggerActivity, BaseDaggerFragment and Binding variants	@AndroidEntryPoint
ViewModelCreator, ViewModelFactory	No longer needed with Hilt

LiveData Components

Removed	Replacement
LiveEvent, LiveEventBus	Event with Channel-based events
DefaultValueLiveData, DefaultValueMediatorLiveData	StateFlow or Compose State
NonNullLiveData	StateFlow or Compose State
UiData, UiDataExtensions, UiDataMediator	StateFlow or Compose State
LiveDataExtensions, LiveDataUtils	Kotlin Flow operators

DataBinding

All DataBinding support has been removed. Use Jetpack Compose instead.

UseCase API Changes

UseCase is now an interface

UseCase<ARGS, T> changed from an abstract class to an interface. Update all definitions:

// Before
class LoginUseCase : UseCase<LoginData, User>() { ... }

// After
class LoginUseCase : UseCase<LoginData, User> { ... }

The deferred property that tracked cancellation has been removed — cancellation is now managed internally via CoroutineScopeOwner.useCaseJobPool.

FlowUseCase is now an interface

Same change applies to FlowUseCase:

// Before
class ObserveUserUseCase : FlowUseCase<Unit, User>() { ... }

// After
class ObserveUserUseCase : FlowUseCase<Unit, User> { ... }

The job property has been removed. The running job is stored in useCaseJobPool.

executeMapped removed

executeMapped has been removed from FlowUseCase. Apply transformations inside build() instead:

// Before
flowUseCase.executeMapped(Unit, transform = { it.name }) {
    onNext { name -> /* ... */ }
}

// After
class ObserveUserNamesUseCase : FlowUseCase<Unit, String> {
    override fun build(args: Unit): Flow<String> =
        userStore.observeUsers().map { it.name }
}

execute uses context parameters

The execute extensions are now declared with Kotlin context parameters. Context parameters are stable as of Kotlin 2.4, so no compiler flag is needed — call execute(...) directly from inside any CoroutineScopeOwner (e.g. a ViewModel or Component) and the receiver is resolved automatically. The call sites remain syntactically the same as before:

loginUseCase.execute(args) { onSuccess { /* ... */ } }

CoroutineScopeOwner Changes

coroutineScope renamed to useCaseScope

The coroutineScope property on CoroutineScopeOwner has been renamed to useCaseScope. Update any custom CoroutineScopeOwner implementations:

// Before
override val coroutineScope: CoroutineScope = viewModelScope

// After
override val useCaseScope: CoroutineScope = viewModelScope

useCaseJobPool is now required

Custom CoroutineScopeOwner implementations must also provide useCaseJobPool:

override val useCaseJobPool: MutableMap<Any, Job> = mutableMapOf()

BaseViewModel and BaseCoreViewModel from Arkitekt already provide both — only custom implementations need to be updated.

Result Type Migration

Arkitekt's custom Result<VALUE> sealed class has been removed. The sync-execute variant now returns kotlin.Result<T>.

Replacing extension functions

Old (Arkitekt Result)	New (kotlin.Result)
.getOrNull()	.getOrNull() ✓ built-in
.getOrDefault(v)	.getOrDefault(v) ✓ built-in
.getOrElse { }	.getOrElse { } ✓ built-in
.getOrThrow()	.getOrThrow() ✓ built-in
.getOrCancel { }	.getOrCancel { } from cr-usecases
.map { }	.map { } ✓ built-in
.fold(onSuccess, onError)	.fold(onSuccess, onFailure) ✓ built-in
tryCatch { }	runCatching { } ✓ built-in

Destructuring

kotlin.Result does not support destructuring declarations. Replace any val (value, error) = result calls with explicit getOrNull() / exceptionOrNull() calls.

Migration Path

1. Upgrade toolchain to AGP 9.1, Gradle 9.4, Kotlin 2.4, JDK 17
2. Remove multidex and Jetifier from gradle.properties
3. Add ksp("org.jetbrains.kotlin:kotlin-metadata-jvm:2.4.0") if you hit Hilt metadata parsing errors (google/dagger#5001)
4. Replace Fragment/Activity base classes with ComponentActivity + @AndroidEntryPoint
5. Replace LiveData with StateFlow or Compose State
6. Replace LiveEvent with Channel-based Event system
7. Migrate UI to Jetpack Compose
8. Replace old BaseViewModel with BaseCoreViewModel or BaseViewModel
9. Replace Dagger 2 with Dagger-Hilt
10. Update UseCase/FlowUseCase from abstract class to interface (remove () from supertype)
11. Remove executeMapped calls — apply mapping in build() instead
12. Rename coroutineScope → useCaseScope in custom CoroutineScopeOwner implementations; add useCaseJobPool
13. Replace custom Result usage with kotlin.Result extensions