iOS Push Notification Setup

import PushKit

private var pushRegistry = PKPushRegistry.init(queue: DispatchQueue.main)
...

func initPushKit() {
  pushRegistry.delegate = self
  pushRegistry.desiredPushTypes = Set([.voIP])
}

extension AppDelegate: PKPushRegistryDelegate {

    // New push notification token assigned by APNS.
    func pushRegistry(_ registry: PKPushRegistry, didUpdate credentials: PKPushCredentials, for type: PKPushType) {
        if (type == .voIP) {
            // This push notification token has to be sent to Telnyx when connecting the Client.
            let deviceToken = credentials.token.reduce("", {$0 + String(format: "%02X", $1) })
            UserDefaults.standard.savePushToken(pushToken: deviceToken)
        }
    }

    func pushRegistry(_ registry: PKPushRegistry, didInvalidatePushTokenFor type: PKPushType) {
        if (type == .voIP) {
            // Delete incoming token in user defaults
            let userDefaults = UserDefaults.init()
            userDefaults.deletePushToken()
        }
    }

    /**
     This delegate method is available on iOS 11 and above. 
     */
    func pushRegistry(_ registry: PKPushRegistry, didReceiveIncomingPushWith payload: PKPushPayload, for type: PKPushType, completion: @escaping () -> Void) {
        if (payload.type == .voIP) {
            self.handleVoIPPushNotification(payload: payload)
        }

        if let version = Float(UIDevice.current.systemVersion), version >= 13.0 {
            completion()
        }
    }

    func handleVoIPPushNotification(payload: PKPushPayload) {
        if let metadata = payload.dictionaryPayload["metadata"] as? [String: Any] {

            let callId = metadata["call_id"] as? String
            let callerName = (metadata["caller_name"] as? String) ?? ""
            let callerNumber = (metadata["caller_number"] as? String) ?? ""
            let caller = callerName.isEmpty ? (callerNumber.isEmpty ? "Unknown" : callerNumber) : callerName
            

            let uuid = UUID(uuidString: callId)
            
            // Re-connect the client and process the push notification when is received.
            // You will need to use the credentials of the same user that is receiving the call. 
            let txConfig = TxConfig(sipUser: sipUser,
                                password: password,
                                pushDeviceToken: "APNS_PUSH_TOKEN")
                                
                        
            //Call processVoIPNotification method 
        
            try telnyxClient?.processVoIPNotification(txConfig: txConfig, serverConfiguration: serverConfig,pushMetaData: metadata)
            

            
            // Report the incoming call to CallKit framework.
            let callHandle = CXHandle(type: .generic, value: from)
            let callUpdate = CXCallUpdate()
            callUpdate.remoteHandle = callHandle
            callUpdate.hasVideo = false

            provider.reportNewIncomingCall(with: uuid, update: callUpdate) { error in
                  if let error = error {
                      print("AppDelegate:: Failed to report incoming call: \(error.localizedDescription).")
                  } else {
                      print("AppDelegate:: Incoming call successfully reported.")
                  }
            }
    }
}

 
 let txConfig = TxConfig(sipUser: sipUser,
                         password: password,
                         pushDeviceToken: "DEVICE_APNS_TOKEN",
                         //You can choose the appropriate verbosity level of the SDK. 
                         logLevel: .all)

 // Or use a JWT Telnyx Token to authenticate
 let txConfigToken = TxConfig(token: "MY_JWT_TELNYX_TOKEN",
                             pushDeviceToken: "DEVICE_APNS_TOKEN",
                             //You can choose the appropriate verbosity level of the SDK. Logs are disabled by default
                             logLevel: .all)

telnyxClient.disablePushNotifications()