Upgrade problem from 12.0.4 to 13

I migrated my nextcloud to a new server, running ubuntu 18.04 and php7.1

And nextcloud 12 was running fine, so I then backed up my nextcloud www dir, and started the update from the web gui. The update seemed to have run correctly as is was all green checkmarks. But when returning to the login page it was just white… then i realized that i may not have update all the apps before i did the update, and then is did something stupid…

I decided to just revert back to my nextcloud backup dir, and nextcloud was running again.
There i updated my apps, and installed caniupdate, and all said yes its fine.

The i tried to update nextcloud (again) But now when i try to go to the update page, the page already have green checkmarks at all the bulletpoints, and when i click update nothing happens, i just get redirected back to my home dir.

I know i fucked this up slightly. But is there any way to save this, so that i can update to Nextcloud 13 ?

I guess the database thinks it v13 and php thinks its v12.

I think we need a bit more information about this error from your logfiles. Like this it could be even a theme or app.