Update :
It seems that we’ve also managed to fix the last minor issues caused by the upgrade. For instance, there was a problem with logging users out, which resulted in an error. This has been resolved today, and during the process (which lasted 2-3 minutes), there was an unfortunate error where posts were made from the wrong user accounts. There was no access to others' accounts; it just posted incorrectly.
Additionally, we have split this thread in two, so that ONLY errors are posted here in this thread – no eye candy, possible changes, or improvements (that are not errors) to make things better,︀ prettier, or for personal preferences.
If there are more errors, feel free to report them︁ here in this thread, the rest into the below thread.