Originally Posted by
Oldguyonoldbike
As mentioned above, the design of the front derailleur changed around 2015 or 2016. I understand that earlier shifters are not compatible with the new front derailleurs.
Among lower level groups (the ones I can afford) Campagnolo also claims that the older shifters (Athena) are incompatible with newer rear derailleurs (Centaur, Potenza), but I doubt that is entirely the case.
11 spd SR/Record/Chorus changed in 2015. The updated parts have an "A" in a box on them, and are compatible with the pre-2015 parts as follows:
I'm not sure what the cross-compatibility with Centaur/Athena/Potenza is.