I am using PJSIP library in my iOS application, and I could see that whenever the messages and send to the application its getting delivered if the application in in foreground. But in the case of background mode I could see that the messages are not getting delivered in some iOS devices. In my case I am getting messages in iPhone 4s,5s etc but not receiving the messages in iPhone 6, 6 plus etc, in those devices the message call back method on_pager are getting triggered when the application come to foreground. Any help on this issue is appreciated. *Thanks & Regards* *Kannan Prasad*