We have the following problem, a friend of mine got Monopoly Plus, I have the Monopoly Funpack, but we can't play together because we don't seem to have the same version, even though we both have the monopoly plus version with it.
Do you both have PS +?
Had the same problem a couple of years ago. In a nutshell: You can't play together unless you have exactly the same game.
This is independent of PS + or anything else. It is simply a failure on the part of Ubis…
Have a good time!