Since the new beta is released, it seems to have my old data (V5).  What’s the best way to get my data from the old beta back?

I notice that the first beta expires soon.

Don’t worry, I took a chance and deleted all the old data, backed up from the first beta and restored it to the new beta.

Backup from old, restore to new.

If you synchronize via a cloud provider, you should also be able to manually "update" the file system. The old beta used a subdirectory "Enpass6 Beta", the new one doesn't ... so simply move the vault out of that directory. (Or better yet: copy it out so you have a backup :))