code: protected static void getRegistrationId(OrtcClient ortcClient){
  		if (checkPlayServices(ortcClient)) {
              gcm = GoogleCloudMessaging.getInstance(ortcClient.appContext);
  
              if (ortcClient.registrationId.isEmpty()){
                  String regid = getRegistrationId(ortcClient.appContext);
                  ortcClient.registrationId = regid;
                  if (regid.isEmpty()) {
                      registerInBackground(ortcClient);
                  }
              }
  
          } else {
          	ortcClient.raiseOrtcEvent(EventEnum.OnException, ortcClient, new OrtcGcmException("No valid Google Play Services APK found."));
          }
  	}
docs: private final static int PLAY_SERVICES_RESOLUTION_REQUEST = 9000;