It's a bloody disaster. I had a whole way of doing things resolved using a series of plugins and none of them are now available. I've been through every thread on here (and elsewhere) and the bottom line is that the whole thing is screwed.
I even spent hours following a process from an option under Help > Manage Extensions. Do yourself a favour, don't bother. It doesn't work, it just opens up the Extensions manager and no matter what you do, you cannot access the extensions at all.
Thanks Adobe!