This ties in with #14229 — it would be great if there was a way to select the version of Flutter to use from the flutter tool. Currently to my understanding the manual process to do so is:

$ cd flutter
$ git checkout [branch, tag or commit hash]
$ cd ../my-app/
$ flutter packages get

(assuming both the flutter folder and the my-app folder live in the same directory)

What would be nice would be able to use a command like flutter switch-to [version] (e.g., flutter switch-to 0.0.20). Ideally running flutter run or flutter build could do this automatically, but that poses the question of how it would work for people working on multiple projects using different versions of Flutter at the same time.