I understand Game center was removed with iOS 10 however my iPad is running 9.3.5. I still have the Game Center app, and I can send friend requests but the request is not received therefore cannot be accepted
iPad Mini Wi-Fi, iOS 9.3.5, null
It seems when Apple took game center away for iOS10 they also took away most of the background support for game center, including add friends.
The plan is for each game's developers to put friending into play on a per game basis so all you can do is wait for that to happen. I understand that friending via facebook still works so if you want to do that you can can try it that way.
Why can't I add friends in Game Center on an iPad running 9.3.5
