iOS 13 not getting VoIP Push Notifications in background

Question

I'm developing a softphone in Swift using CallKit and PushKit. Before iOS 13, VoIP notifications were working perfectly. But after the iOS 13 update, my app isn't getting VoIP push notification when it's in background. In foreground didReceiveIncomingPushWith is called, but in background it isn't called.

How can I fix this issue?

Code

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    print("\(#function)")
    let voipPushResgistry = PKPushRegistry(queue: nil)
    voipPushResgistry.delegate = self
    voipPushResgistry.desiredPushTypes = [PKPushType.voIP]

    return true
}

func pushRegistry(_ registry: PKPushRegistry, didInvalidatePushTokenFor type: PKPushType) {
    print("\(#function) token invalidated")
}

func pushRegistry(_ registry: PKPushRegistry, didUpdate credentials: PKPushCredentials, for type: PKPushType) {
    let deviceToken = credentials.token.reduce("", {$0 + String(format: "%02X", $1) })
    print("\(#function) token is: \(deviceToken)")
}

func pushRegistry(_ registry: PKPushRegistry, didReceiveIncomingPushWith payload: PKPushPayload, for type: PKPushType, completion: @escaping () -> Void) {
    print("\(#function)")
    print("It worked..")
    if type == .voIP {
        print("Uygulama aktif")
    }
}

Thanks.

Answer 1

If you build the app with Xcode 11 (and iOS 13 SDK) PushKit won't work any longer if you fail to report to CallKit.

On iOS 13.0 and later, if you fail to report a call to CallKit, the system will terminate your app. Repeatedly failing to report calls may cause the system to stop delivering any more VoIP push notifications to your app. If you want to initiate a VoIP call without using CallKit, register for push notifications using the UserNotifications framework instead of PushKit.

https://developer.apple.com/documentation/pushkit/pkpushregistrydelegate/2875784-pushregistry