Something that is understated in this changelog is the resolution of the CORS permissions.
What this means is that wefwef and other web-based (or PWA) clients can now access all servers that are running 0.18.1 or newer.
Prior to this update wefwef has actually been proxying all user requests through their server, which not only includes all of your browsing and commenting, but your login token. While there's no reason to distrust aeharding (the wefwef dev), this was an uneccesary security risk and also meant you could only login and browse instances that wefwef had whitelisted.
Thankfully this is now all resolved, so now we just need to wait for everyone to make the transition.
In your settings, make sure the theme is off of the crystals theme. That or hard reload (ctrl+alt+R), as I've moved the theme back to darkly until I can fix the theme. A lot of UI things changed in these updates.