I'm working on my game (which has already been released), and I'd like to work on the multiplayer aspects. My changes make it incompatable with past versions. I've created a new version number in the "App Store Connection", and stated that it is not backwards compatable with older versions. I've updated the version number in my game, but I have not submitted it yet as I'm still working on it.
When I test my game, it is connecting to actual users running an older version of the game. How do I prevent that?
According to the docs [Testing Your App], testing multiplayer compatibility requires some configuration in App Store Connect. Are you saying you did that by taking steps to not allow live users to see results and it's not working?
Multiplayer compatibility settings determine which users running different versions of your app see their results together in Game Center. You access the multiplayer compatibility settings on Versions in the App Details page of your app.