I have upgraded from 5.0-rc8a following the recommended steps, and everything went well. I was able to start the array and see my shared folder/files.
The next day I started unraid and was not able to mount the disks. Unraid just seems to hang trying to mount them. I had to manually power off unraid. I tried again but had the same issue.
I then booted up unraid and put the system into maintenance and was able to run a parity check. Once this completed I restarted unraid and tried to bring the disks online but unraid just hangs.