When I try to post a reply, even if I allow everything, then I get the message "an error occurred (status: 0)". Which looks like something else is broken. Also I checked with Edge, I had no problems there.
Edit: This update broke also gmx.de (email provider, can't access emails) and gerrit reviews (can't login). Those worked previously and I didn't touch their settings.
Reddit posting doesn't work
Reddit posting doesn't work
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0