We have been developing an application for secure chat and currently it is in the testing stage.This application is a secure chat application which has messaging, call and group chat facility.We are using MQTT client for the communication between devices.We have limited dependency on server ,we are not storing any kind of messages in the server.Client wants to use this application in a secure environment where only device to device communication exist with limited server usage.So once the device goes to background and terminated by the system we were unable to receive messages since it is a device to device communication.Currently we are using Voip push notification for managing call and at the same time for waking the application if it is offline.From the latest iOS 13 release we are restricted to use Voip notification only for Pushkit. This make our app crash when we receive another wakeup messages