First, the add-ons were identified as Legacy and wouldn't work; however, a work-around solution (restart in Safe Mode, exit, restart normally) restored them to working. Then, the work-around wouldn't work anymore. A couple of days after that, the Legacy add-ons weren't even listed anymore -- and any attempt to reinstall them was met with a message that the add-on was incompatible and would not be installed.
Same here. Now I can't get to my logins and passwords without going to Safe Mode and a couple of my popular add-ons are not working either. While investigating the latter problem, I came across these articles on how Firefox was going to bomb its own browser in a couple of weeks.