Downgrading in TwistedBrush Pro Studio is only partially supported. This means that if you install a earlier program version after using a newer one, you may encounter some issues. While the ”Reset All” option in the File menu will fix some things, it's possible that some created content (such as saved brush shortcuts, for example) won't be useable in the older version.

To downgrade the best thing to do is install the program into a different folder location.