This is somewhat strange (not that any of the above hasn't been) - I got this window earlier today and didn't notice it
I put it up here because it gives the exact build/version details.
The server software has been updated. It is recommended that you reload your browser so that you are up to date.
Old version: 6.0.8_GA_2661 20100820033514 20100820-0336 NETWORK
New version: 6.0.8_GA_2661 20100820033955 20100820-0341 NETWORK
Would you like to reload the browser now? Warning: if you choose not to reload, there is a chance you will encounter errors.
The installation worked fine for mail today but the Admin UI is still strange. Before it was very clean, responsive, etc. Now the formatting is slightly off, and it is missing features (again, Backups is the biggest one...)
I don't know what to try next. I was following official, documented steps for a (eventually) required migration on a supported platform. Strange.
Lastly - if anyone has any suspicians and would like to see them, I'm happy to post more logs, conf files, etc.