Matches across different apps of a Game Center group

Question

I have a free app (with ads) that allows players to play online games through Game Center. Now I want to create the ad-free (paid) version of the app. So I create a Game Center group and move there all my leaderboards and achievements. The problem is: can a player of the paid app play against a player of the free app? I'm using Game Center only, no server of my own. From a few quick experiments, it seems that the two apps live on two parallel worlds, and if one uses the classical findMatchForRequest:withCompletionHandler: one can only find matches within the same app and not across apps in the same group. Is there any way around this?

Answer 1

It is actually possible to address this issue in a rather simple way, although it was not so evident what to look for.

The Game Center Programming guide actually states that "You can create distinct games (with different bundle identifiers) and still allow them to play against each other."

So you have to click "View Details" of one of your apps. There, if you have enabled Game Center for your app, edit "Multiplayer Commpatibility" and add the other app to the list. Now you can play matches across different apps.