# Deprecated imperative apply of Flutter's Gradle plugins > How to migrate your Flutter app's Android Gradle build files to the new, declarative format. :::important These breaking change docs are accurate, as of the release under which they are published. Over time, the workarounds described here might become inaccurate. We don't, in general, keep these breaking change docs up to date as of each release. The [breaking change index file](/release/breaking-changes) lists the docs created for each release. ::: ## Summary To build a Flutter app for Android, Flutter's Gradle plugins must be applied. Historically, this was done imperatively with Gradle's [legacy, imperative apply script method][]. In Flutter 3.16, support was added for applying these plugins with Gradle's [declarative plugins {} block][] (also called the Plugin DSL) and it is now the recommended approach. Since Flutter 3.16, projects generated with `flutter create` use the Plugin DSL to apply Gradle plugins. Projects created with versions of Flutter prior to 3.16 need to be migrated manually. Applying Gradle plugins using the `plugins {}` block executes the same code as before and should produce equivalent app binaries. To learn about advantages the new Plugin DSL syntax has over the legacy `apply` script syntax, see [Gradle docs][plugins block]. Migrating the app ecosystem to use the new approach will also make it easier for Flutter team to develop Flutter's Gradle plugins, and to enable exciting new features in the future, such as using Kotlin instead of Groovy in Gradle buildscripts. ## Migrate ### android/settings.gradle First, find the values of the Android Gradle Plugin (AGP) and Kotlin that the project currently uses. Unless they have been moved, they are likely defined in the buildscript block of the `/android/build.gradle` file. As an example, consider the `build.gradle` file from a new Flutter app created before this change: ```groovy buildscript { ext.kotlin_version = '1.7.10' repositories { google() mavenCentral() } dependencies { classpath 'com.android.tools.build:gradle:7.3.0' classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version" } } allprojects { repositories { google() mavenCentral() } } rootProject.buildDir = '../build' subprojects { project.buildDir = "${rootProject.buildDir}/${project.name}" } subprojects { project.evaluationDependsOn(':app') } tasks.register("clean", Delete) { delete rootProject.buildDir } ``` The AGP version is the number that comes at the end of the line `classpath 'com.android.tools.build:gradle:7.3.0'`, so `7.3.0` in this case. Similarly, the Kotlin version comes at the end of the line `ext.kotlin_version = '1.7.10'`, in this case `1.7.10`. Next, replace the contents of `/android/settings.gradle` with the following, remembering to replace `{agpVersion}` and `{kotlinVersion}` with previously identified values: ```groovy pluginManagement { def flutterSdkPath = { def properties = new Properties() file("local.properties").withInputStream { properties.load(it) } def flutterSdkPath = properties.getProperty("flutter.sdk") assert flutterSdkPath != null, "flutter.sdk not set in local.properties" return flutterSdkPath }() includeBuild("$flutterSdkPath/packages/flutter_tools/gradle") repositories { google() mavenCentral() gradlePluginPortal() } } plugins { id "dev.flutter.flutter-plugin-loader" version "1.0.0" // apply true id "com.android.application" version "{agpVersion}" apply false id "org.jetbrains.kotlin.android" version "{kotlinVersion}" apply false } include ":app" ``` If you made some changes to this file, make sure they're placed after `pluginManagement {}` and `plugins {}` blocks, since Gradle enforces that no other code can be placed before these blocks. The settings Flutter Gradle Plugin (`dev.flutter.flutter-plugin-loader`) should not have apply false (the default is true) or should be explicitly set to true. ### android/build.gradle Remove the whole `buildscript` block from `/android/app/build.gradle`, also need to be made. First, remove the following 2 chunks of code that use the legacy imperative apply method: ```groovy diff - def flutterRoot = localProperties.getProperty('flutter.sdk') - if (flutterRoot == null) { - throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.") - } ``` ```groovy diff - apply plugin: 'com.android.application' - apply plugin: 'com.jetbrains.kotlin.android' - apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle" ``` Now apply the plugins again, but this time using the Plugin DSL syntax. At the very top of your file, add: ```groovy plugins { id "com.android.application" id "kotlin-android" id "dev.flutter.flutter-gradle-plugin" } ``` `"dev.flutter.flutter-gradle-plugin"` is the project Flutter Gradle Plugin, which is a different string than the value applied in settings.gradle(.kts) (`"dev.flutter.flutter-plugin-loader"`). Finally, if your `dependencies` block contains a dependency on `"org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"`, then remove that dependency. ```groovy diff dependencies { - implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version" } ``` If it was the only dependency in the `dependencies` block, then you can instead remove the block entirely. ### Validation Execute `flutter run` to confirm that your app builds and launches on a connected Android device or emulator. ## Examples ### Google Mobile Services and Crashlytics If your app was using Google Mobile Services and Crashlytics, remove the following lines from `/android/build.gradle`: ```groovy diff buildscript { // ... dependencies { // ... - classpath "com.google.gms:google-services:4.4.0" - classpath "com.google.firebase:firebase-crashlytics-gradle:2.9.9" } } ``` Then remove these 2 lines from `/android/app/build.gradle`: ```groovy diff - apply plugin: 'com.google.gms.google-services' - apply plugin: 'com.google.firebase.crashlytics' ``` To migrate to the new, declarative-apply syntax for the GMS and Crashlytics plugins, add them to `plugins` block in your app's `/android/settings.gradle` file. The additions should look similar to the following, but with your desired plugin versions, likely matching the ones you removed from the `/android/build.gradle` file. ```groovy diff plugins { id "dev.flutter.flutter-plugin-loader" version "1.0.0" id "com.android.application" version "{agpVersion}" apply false id "org.jetbrains.kotlin.android" version "{kotlinVersion}" apply false + id "com.google.gms.google-services" version "4.4.0" apply false + id "com.google.firebase.crashlytics" version "2.9.9" apply false } ``` Add the following lines to `/android/app/build.gradle`: ```groovy diff plugins { id "com.android.application" id "dev.flutter.flutter-gradle-plugin" id "org.jetbrains.kotlin.android" + id "com.google.gms.google-services" + id "com.google.firebase.crashlytics" } ``` ## Timeline Support in stable release: 3.16.0 Recommended in stable release: 3.19.0 ## References Gradle build files generated by `flutter create` differ across Flutter versions. For a detailed overview, see [issue #135392][]. You should consider using the latest versions of build files. [legacy, imperative apply script method]: https://docs.gradle.org/8.5/userguide/plugins.html#sec:script_plugins [declarative plugins {} block]: https://docs.gradle.org/8.5/userguide/plugins.html#sec:plugins_block [plugins block]: https://docs.gradle.org/current/userguide/plugins.html#plugins_dsl_limitations [issue #135392]: https://github.com/flutter/flutter/issues/135392