Solved: How to downgrade Flutter SDK (Dart 1.x)


Asked by Stephane on March 24, 2018 (source).

I upgraded my Flutter SDK and now my project is broken. I need to basically revert back to a Flutter SDK which uses Dart 1.x.

I tried the following in the pubspec.yaml,

  sdk: ">=1.19.0 <2.0.0"
  flutter: "^0.1.2"

    sdk: flutter

but now the project just simply doesn't build.

Running "flutter packages get" in binformed...
Package binformed requires Flutter SDK version ^0.1.2 but the current SDK is 0.2.5-pre.38.
pub get failed (1)

Do i need to uninstall the SDK and reinstall it?


Question answered by Rémi R (source).

Flutter is versioned using git. Changing the Flutter version is as simple as changing git branch.

There are 2 different ways:

  • flutter channel <branch> (example: flutter channel stable)

This command is used to change between branches – usually stable/dev/beta/master. We can also put a specific commit id from git.

  • flutter downgrade <version> (example: flutter downgrade v1.2.1)

This command will use a specific version number. You can have the list of the available version numbers using flutter downgrade or here

After this, run any Flutter command (such as flutter doctor), and Flutter will take care of downloading/compiling everything required to run this version.