VOIP/SIP integration in the dialler is the big one for me. There are VOIP apps for iOS but they generally do not work nearly as well as the integrated VOIP sys

VOIP/SIP integration in the dialler is the big one for me. There are VOIP apps for iOS but they generally do not work nearly as well as the integrated VOIP system in the dialler. iOS’ obsession with control and killing background apps makes it almost impossible to write a decent VOIP app.