I'm still running FF 56.0.2 because I can't live without Tab Mix Plus.
The official line was to wait for the update but about:studies never came up with anything even after 24 hours of waiting and everyone was saying it was fixed but it wasn't for me, I presume because nobody cares about the refugees stuck on pre-add-on breaking versions.
So it was completely broken until I finally found a reddit thread that described how to use the developer console to manually import the certificate extracted from the fix.
That worked, but it enabled all my add-ons, even ones that were previously disabled.
Bloody irritating. I didn't even know that it was possible to break things remotely like this.