Multiplayer session discovery on iOS 14

I had session discovery for my game working on my iOS devices until I upgraded them to iOS 14. Now session discovery does not work, but I can still connect directly using device IP address.

It turns out that Apple added an entitlement requirement for multicast (needed for session discovery) to iOS 14, so it makes sense that session discovery stopped working for me. There is a a procedure for adding this entitlement to your app ID, but it requires making a request to Apple via a form in the Developer support pages. I made this request and got an email asking for more information, specifically:

Thank you for your interest in Multicast Networking. Can you please provide more details on which multicast or broadcast protocol (IP address and port) you need to use? What messages are exchanged between devices?

I don’t know what the answers are to these questions. Does anyone here know what port and messages are used for session discovery (does IP address even make sense for multicast?)?

I replied to the email basically just saying I was using Unreal Engine and wasn’t sure what messages were being sent during session discovery, and a few days later I got an email saying my app had been approved and I was able to generate a new provisioning profile with the entitlement added.

Now I just need to figure out how to add an entitlement to an Unreal Engine project - this seems to be an unanswered question.