I have a couple of relatively minor problems following the upgrade.
Firstly, my text is no longer being converted into HTML entities (eg. — isn’t becoming —; ” ” isn’t becoming “ ??, etc).
Also, comment author URLs are messing up a bit. I think it’s happening for people who don’t enter the ‘https://’ at the beginning, resulting in broken links. I am sure this never happened before. The strange thing is, the URLs appear fine on the Favatar links.