We have followed the guide to obtaining and enabling multicast entitlement for our app as detailed on this forum post. - https://www.example.com/ The multicast entitlement:    <key>com.apple.developer.networking.multicast</key>   <true/> is in the provisioning profile. It's in the entitlements file. It's in the App ID capabilities. Target Build Settings references the .plist containing the entitlement. There are no build warnings about entitlements. There are no warnings on upload to AppStoreConnect. The app receives UDP OK on-device when building from Xcode. It doesn't receive UDP when installing the same build from TestFlight. Any suggestions where to look next are most welcome. We are out of ideas apart from starting a long series of low level tests to isolate the issue, but don't really have the time to debug the App Store Connect provisioning system. Summary: We have pre iOS 14 devices working fine alongside an iOS 14 device that works fine until TestFlight. With all the multicast enablement steps followed.