I think it used to say what was missing.
Meantime ..all you can do ist take the advice inthe notice.
eg. copy your FX plugins, presets etc across to 7.0
I don't remember ever installing any FX. I think maybe it's talking about the Blackmagic presets, but I read somewhere that CC doesn't need all those — that's supposed to a benefit to the new version I think. Do you think I should reinstall the Decklink drivers?
Install it if you use it or did previously.
The message indicates that it is a Sequence Preset issue.
Go back to the other version and see what was used there.
This could be related to old Blackmagic presets. FYI, this message doesn't necessary mean there will be any ill affects. You should be just fine continuing without issue.