If you updated recently and haven't removed anything, snap list cherrytree --all will show you old versions you still have cached and snap revert cherrytree should restore to the previous version. Maybe there's a way to run something like snap refresh cherrytree --channel=$VERSION but I couldn't figure it out before I had to move on. Either that or download the official appimage on the developers website: https://www.giuspen.com/cherrytree/