Sorry to hear you were having issues on the update with your moderator CP. I am not seeing that on my end, but will do some testing to see if I can replicate.
With the upgrade part of things, if you change a PHP version, you would need to check to ensure you have the minimum requirements for the software after doing this. It would eventually be picked up in the admin CP, and would at times even break the software. However these are already minimum requirements even before the upgrade