I am developing an App that will enable voice calls between users through webrtc. When the user opens the App and switches the App to the background, the user will receive the incoming call notification through Silent Push Notifications (not PushKit). My question is as follows, If set UIBackgroundModes to voip and do not use PushKit and CallKit, will this cause the background App to be unable to use webrtc voice calls (requires network, microphone, and audio permissions)? Can I set UIBackgroundModes = audio combined with AVAudioSession playAndRecord instead of setting UIBackgroundModes to voip, so that I can use the microphone and audio in the background to implement webrtc voice calls? Thanks for your help.