Skip to main content

Built-in Kotlin migration for plugin authors

Migrate Flutter plugins to use built-in Kotlin.

Migrate your Flutter plugin

#

This guide outlines the migration steps specifically for plugin authors.

Update the Gradle file

#

First, find the kotlin-android plugin (or the org.jetbrains.kotlin.android plugin). It is likely located in the plugins block of the <plugin-project>/build.gradle or the <plugin-project>/build.gradle.kts file. If you use the legacy apply syntax, it will be located in the Groovy-based <plugin-project>/build.gradle file, as this syntax is not supported in Kotlin DSL.

The following examples demonstrate how to migrate a Flutter plugin:

Before:

<app-src>/android/build.gradle(.kts)
kotlin 
plugins {
    id("com.android.library")
    id("kotlin-android")
    // ...
}
​
android {
    // ...
    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_17.toString()
    }
    // ...
}
​
// ...

Next, remove the kotlin-android plugin and the kotlinOptions block:

<app-src>/android/build.gradle.kts
kotlin 
plugins {
    id("com.android.library")
    id("kotlin-android")
    // ...
}
​
android {
    // ...
    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_17.toString()
    }
    // ...
}

Add the kotlin.compilerOptions{} DSL block with the following:

<app-src>/android/build.gradle.kts
kotlin 
kotlin {
    compilerOptions {
        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
    }
}

Here is how the file will likely end up:

After:

<app-src>/android/build.gradle(.kts)
kotlin 
plugins {
    id("com.android.library")
    // ...
}
​
android {
    // ...
}
​
kotlin {
    compilerOptions {
        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
    }
}
​
// ...

Before:

<app-src>/android/build.gradle
groovy 
apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
// ...
​
android {
    // ...
    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_17.toString()
    }
    // ...
}
​
// ...

Next, remove the kotlin-android plugin and the kotlinOptions block:

<app-src>/android/build.gradle
groovy 
apply plugin: 'com.android.library'
apply plugin: 'kotlin-android'
 ...
​
android {
    // ...
    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_17.toString()
    }
    // ...
}

Add the kotlin.compilerOptions{} DSL block with the following:

<app-src>/android/build.gradle
groovy 
kotlin {
    compilerOptions {
        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
    }
}

Here is how the file will likely end up:

After:

<app-src>/android/build.gradle
groovy 
apply plugin: 'com.android.library'
// ...
​
android {
    // ...
}
​
kotlin {
    compilerOptions {
        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
    }
}
​
// ...

Update the plugin's pubspec.yaml

#

Using the kotlin.compilerOptions {} DSL block requires a minimum Kotlin Gradle Plugin (KGP) version of 2.0.0. Beginning with Flutter 3.44, the minimum required KGP version is 2.0.0. To ensure that apps using your plugin can safely migrate to built-in Kotlin, you should require a minimum Flutter version of 3.44 for this plugin version.

Since you are updating the minimum Flutter version, you must also update the minimum associated Dart version.

Update the minimum Flutter version and the minimum Dart version:

<plugin-project>/pubspec.yaml
yaml 
...
​
vironment:
 sdk: ^<previous-dart-minimum>
 sdk: ^3.12.0
 flutter: ">=<previous-flutter-minimum>"
 flutter: ">=3.44.0"
​
...

Here is how the file will likely end up:

<plugin-project>/pubspec.yaml
yaml 
# ...
​
environment:
  sdk: ^3.12.0
  flutter: ">=3.44.0"
​
# ...

Update the plugin's CHANGELOG.md

#

Include your changes in the CHANGELOG of the newly released plugin version:

<plugin-project>/CHANGELOG.md
markdown 
## <new-plugin-release-version>
​
- Updates minimum supported SDK version to Flutter 3.44/Dart 3.12.
- Migrates to built-in Kotlin
​
 ...

Validate

#

Execute flutter run or flutter build apk to confirm that your plugin example app builds and launches on a connected Android device or emulator.

If your plugin example app also applies KGP, then you will also have to migrate the example app. Follow the migration guide for app developers to migrate your example app.

Unless stated otherwise, the documentation on this site reflects Flutter 3.41.5. Page last updated on 2026-04-09. View source or report an issue.