title: didUpdatePushCredentials not get called
body: <p>I want to implement VoIP notifications in my iOS application, But the <strong>didUpdatePushCredentials</strong> method never got called, I can't get the device token.</p>
  
  <p>I had implemented APNS in the application, May these two services conflict ?</p>
  
  <p>Here is my AppDelegate codes</p>
  
  <pre><code>- (void)application:(UIApplication *)application
      didRegisterUserNotificationSettings:(UIUserNotificationSettings *)notificationSettings {
      LOGI(@"%@", NSStringFromSelector(_cmd));
  
      //register for voip notifications
      self-&gt;pushRegistry = [[PKPushRegistry alloc] initWithQueue:dispatch_get_main_queue()];
      [self-&gt;pushRegistry setDelegate:self];
      [self-&gt;pushRegistry setDesiredPushTypes:[NSSet setWithObject:PKPushTypeVoIP]];
  
      NSLog(@"VoIP push registered");
  
  }
  
  #pragma mark - VoIP push methods
  
  - (void)pushRegistry:(PKPushRegistry *)registry didUpdatePushCredentials:(PKPushCredentials *)credentials forType:(NSString *)type {
      NSLog(@"voip token: %@", credentials.token);
  }
  
  - (void)pushRegistry:(PKPushRegistry *)registry didReceiveIncomingPushWithPayload:(PKPushPayload *)payload forType:(NSString *)type {
      NSDictionary *payloadDict = [payload.dictionaryPayload valueForKey:@"aps"];
      NSString *message = (NSString *)[payloadDict valueForKey:@"alert"];
  
      if ([UIApplication sharedApplication].applicationState == UIApplicationStateBackground) {
          UILocalNotification *localNotification = [[UILocalNotification alloc] init];
          localNotification.alertBody = [message stringByAppendingString:@" - voip"];
          localNotification.applicationIconBadgeNumber = 1;
          localNotification.soundName = @"notes_of_the_optimistic.caf";
  
          [[UIApplication sharedApplication] presentLocalNotificationNow:localNotification];
      } else {
          dispatch_async(dispatch_get_main_queue(), ^{
              UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"VoIP notification" message:message delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
              [alert show];
          });
      }
  
  
      NSLog(@"incoming voip notfication: %@", payload.dictionaryPayload);
  }
  
  - (void)pushRegistry:(PKPushRegistry *)registry didInvalidatePushTokenForType:(NSString *)type {
      NSLog(@"Voip token invalidate");
  }
  </code></pre>
  
  <ul>
  <li>I enabled remote notifications, Certificate and provisioning profiles are installed.</li>
  <li>I can push standard notifications using APNS.</li>
  </ul>
  
  <p>Any solution to get it working ?</p>