Originally posted by Foxglovez:

If a person goes on the test branch, what happens after it goes live in a few weeks? Does the test branch save just disappear or does it convert to a stable save so you can keep playing it and don't lose progression on a new world, or an old one for that matter?

Most likely it works just like any other game update (that is, a world and character get updated regularly to new version and stable release will allow you to continue as normal - it's possible you won't be able to go to test branch and then downgrade back to regular until Mistlands releases properly).

You can just create a backup and test it yourself though.