I have apps the use MultipeerConnectivity Foundation to pass data between iOS devices. Now, none of those apps works. I suspect the because iPhone running 16.4.1 says that "iPad is not supported" when trying to pair devices is the problem. Seeing the iPad is not the problem but connecting and passing data absolutely fail.

Have you found a solution yet? My iPhone 13 running iOS 16.4.1 will not pair with iPad Pro running the same OS. It just says that the iPad is unsupported?!? This renders apps using the MultipeerConnectivity Framework inoperative and worthless.