I just wanted to add that I had exactly the same problem when upgrading vom 6.12 to 7.0. All the configuration, from IP, server-name, description, time zone, ... up to the raid configuration was reset. The `go`-file was completely empty.
Thanks God the whole stick is within a git-repository, so I was able to revert to a commit before the update. Next time I will at least create a backup before updating (as advised, I know, but as since now everything went smoothly on every update ... well ...).
Somehow a wake-up call that also Unraid is not free of problems ...