Additional question: Can "NEAppPushDelegate.appPushManager(:didReceiveIncomingCallWithUserInfo:)" replace "PKPushRegistryDelegate.pushRegistry(:didReceiveIncomingPushWith:for:completion:)"?

Thank you for your reply. We immediately integrated CallKit into our app but faced a problem receiving calls in the background. The app must enable recording before call reportNewIncomingCall. But AVAudioSession cannot change Category to .playAndRecord in the background. In the reference implementation by pjsip (ipjsua), it changes when it receives a VoIP Push. However, our app does not use PushKit because it is used on local networks. Is PushKit required to answer calls in the background?