I have this issue with my iPhone 5s and iPhone 6. When I'm on wifi, I can get notifications from apps like whatsapp etc... Without opening the app, but on cellular , I don't get any notification except if I get into the App, which is very inconvenient since I can't check my phone every minute when I'm out. I have background app refresh enabled , and cellular data turned on for all apps, so what can I do to receive notifications on cellular without having to open the app?