legacy sessions

Is there a way to get a list of missing plugins when opening a legacy session? I have several N3 sessions that I need to continue in N5. I am waiting for N5 to arrive but am messing around in a copy of the session using C5. BFD2 instances are not loading, though I can instantiate new instances of it okay. I am guessing that the latest version of BFD2 changed something and isn’t being recognized as the same plug by C5. Irritating. If I could find out which version was saved in the session, I could probably back out to that version. Hopefully that will solve my immediate problem. Alternatively, I would settle for a way to read out the setting from the old BFD2 instance and recreate them by hand.

I had planned to wait to upgrade until after these mixes were done, but my self destructing G5 had other plans. As I said, irritating. Any help is appreciated.