Hi There,
#1 Beta builds are available for download until we release the product or refresh the beta build with a new one. Beta is an unfinished product so not supported in production but it is free to download and use.
#2 We do not support downgrades the same way we do upgrades. You cannot do online downgrades with the product but there are other way you can downgrade versions if you choose to do that.
#3 The restoring of backups taken with new versions is not a supported scenario either. I’d recommend using export and import to move data back.
thanks
-cihan