If you are on stable right now I cannot recommend a move to tests-passed atm. There is a lot of change going on, particularly with the Front End so it might be worth waiting until that’s settled down and simply wait patiently for 3.4 stable, especially if you are a heavy user of third party Theme Components and Plugins.
Otherwise it’s just a case of updating the branch in app.yml and rebuilding. But that’s not something you can easily reverse.