This explains why I had problems logging in since yesterday, usually I browse through a frontend like Alexandrite or use Jerboa on my phone, spent two hours trying to fix my login info before I gave up and just went to the instance directly.

It does seem extremely odd to upgrade the main instance to 0.19, I wonder if it wasn't intended. As other users mentions lots of features are still not functional and app support is basically nonexistent for 0.19 because of the amount of breaking changes.