VST Connect 5 had to be updated for Cubase/Nuendo 11.0.40/41. That’s why Cubase/Nuendo has version 5.5.20 of VST Connect. It contains only an “internal fix”.
Your connection problem must have another reason. Which VST Connect Performer version is your friend using?
so from your comments, I take it you are involved with programming this part of Cubase ?!? so the error message is pretty clear to me! it states we don’t have the same version. So what should I do to fix it? could I roll back?