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Migrating Flutter Android projects to built-in Kotlin

Update your Flutter Android Gradle files to use built-in Kotlin support. Essential for migrating projects to Android Gradle Plugin 9.0.0+.

Summary

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To build a Flutter app for Android, the Android Gradle Plugin (AGP) must be applied. As of AGP 9.0.0, the following migrations are required to successfully use AGP 9.0.0+.

First, built-in Kotlin is the new default on AGP 9+, meaning any apps using the kotlin-android plugin (also known as the Kotlin Gradle Plugin or KGP) will not build successfully Issue #181383. However, the Flutter team has added temporary support for the legacy Kotlin Gradle Plugin (KGP) in AGP 9.0.0+ Issue #183909. This allows app and plugin developers to safely build their projects regardless of their migration state.

Second, AGP 9.0.0+ will only use the new AGP DSL interfaces. This means any old DSL types will not be recognized. The Flutter team is working on migrating old DSL types to use the new DSL: Issue #180137. In the meantime, the Flutter team has configured the AGP DSL to be compatible with the legacy old AGP DSL types Issue #184838. This ensures app and plugin developers can safely upgrade to AGP 9+.

To ensure compatibility, all apps and plugins must be manually migrated from the legacy Kotlin Gradle Plugin (KGP) to built-in Kotlin. In a future Flutter version, support for applying KGP will be removed Issue #184837.

To learn more about Android Gradle Plugin, see the Android Gradle Plugin docs.

Migrate

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For app developers: See the app developer migration guide.

For plugin authors: See the plugin author migration guide.

Next steps

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  • Remove Support for KGP: In a future version of Flutter, support for applying KGP will be removed Issue #184837. Developers must migrate their projects (apps, plugins, host app projects) or they will be unable to build.

  • Remove DSL Gradle Property: Once the Flutter team completes the migration to the new AGP DSL, the Flutter team will remove support for the old DSL Issue #184839.

Relevant issues:

The Gradle build files in your app vary based on the Flutter version used when your app was created. Consider staying up to date with the latest version of the build files by periodically running flutter upgrade in your app's directory.

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.