What's new in Flutter 3.35

Component theme normalization updates

`AppBarTheme`, `BottomAppBarTheme` and `InputDecorationTheme` were refactored to conform to Flutter's conventions for component themes. `AppBarThemeData`, `BottomAppBarThemeData` and `InputDecorationThemeData` were added to define overrides for the defaults of the component visual properties. Releases of Flutter continue to normalize component themes like these for a more consistent theming experience in the material library.

Redesigned the Radio widget

Introduced the `RadioGroup` widget to centralize `groupValue` management and the `onChanged` callback for a set of `Radio` widgets. As a result, the individual `Radio.groupValue` and `Radio.onChanged` properties have been deprecated.

The Form widget no longer supports being a sliver

Previously, the Form widget essentially acted as a direct wrapper around its child. This design allowed a Form containing a sliver child (e.g., Form(child: other sliver)) to be treated as a sliver itself within a CustomScrollView or similar scrollable parent.

Flutter now sets default abiFilters in Android builds

Starting in Flutter 3.35, the Flutter Gradle Plugin automatically sets `abiFilters` for Android builds to prevent the inclusion of unsupported architectures in release APKs. This change can break custom `abiFilters` specified in your app's `build.gradle` file.

Merged threads on macOS and Windows

Flutter 3.35 merges the UI and platform threads by default on macOS and Windows.

The Visibility widget is no longer focusable by default when maintainState is enabled

This change was introduced to fix an issue where an `IndexedStack`s hidden children would be focusable with keyboard events (see issue) due to the underlying `Visibility` widgets default behavior.

$FLUTTER_ROOT/version replaced by $FLUTTER_ROOT/bin/cache/flutter.version.json

The `flutter` tool will no longer output the `$FLUTTER_ROOT/version` metadata file, and only output `$FLUTTER_ROOT/bin/cache/flutter.version.json`.

Removed semantics elevation and thickness

Both elevation and thickness semantics properties and their related APIs were removed.

Deprecate DropdownButtonFormField value parameter in favor of initialValue

The `value` parameter of the `DropdownButtonFormField` constructor was deprecated in favor of the `initialValue` parameter.

Deprecate app bar color

The `color` parameter in `AppBarTheme` and `AppBarThemeData` constructors and their `copyWith` methods have been deprecated. Use `backgroundColor` instead. This change affects how AppBar themes are configured and might cause deprecation warnings in existing code.

Flutter view no longer hangs after multiple transitions on iOS add-to-app.

- A race condition can cause crashes in the Impeller Vulkan back end.

- Don't crash widget preview when a directory watcher restarts on Windows.

Apps, on all platforms, that extend MenuController class see a compile time failure when building.

Mitigates a memory leak that occurs on Android, when `Activities` are not kept upon exit and an Activity is exited and re-entered.

`flutter analyze --suggestions` supports versions up to Java 25, Gradle 9 and AGP 9, Kotlin 2.2.20.

Fixes an issue that could result in a corrupt pipeline cache when using the Impeller Vulkan back end.

Multiple cursors display correctly.

- On all platforms PlatformDispatchers.instance.engineId no longer returns null after hot restart.

- On iOS 26, fix a bug where platform view's gesture blocking fails and lets touches on Flutter views fall through to underlying...

- Unnecessary output is printed in non-verbose mode.

- On Android, `flutter build apk` may fail to calculate the version code when using `--build-number`.

- When running a Flutter web application in debug mode, the console is spammed with non-fatal error messages.

- Golden test failures can cause the test harness to stall.

- Superellipses may not render correctly when using Impeller.

- Obsolete warning and error messages are shown when switching between build modes in Xcode.

- On Android builds that do not use flutter.minSdkVersion and do use a value lower than 24 in a kotlin build file, correct flutters auto...

- Fixes an issue that prevents (web) screen readers from pressing buttons through keyboard shortcuts.

- Fixes an issue where starting a widget preview fails if Chrome or Edge is not installed.

- Fixes an issue when running a 32-bit process on a 64-bit Windows system.

- Blocks `exynos9820` chip from using the Impeller Vulkan backend.

- Fixes a null assertion when trying to add `@Preview()` to invalid nodes.

- Fixes an issue where WASM builds were incorrectly triggered when dry run is disabled and --wasm is not specified.

- Fixes an ExistingDartDevelopmentServiceException that could be thrown when running flutter run on a device with an existing Dart...