Q:

iOS SDK can you mute or cancel incoming calls

I found various threads here about how muting or canceling incoming calls (or messages) with the iOS SDK is not possible, due to the fact that Apple doesn't want an app to access system level settings. Well in fact not possible with the official tools, which means that if you somehow manage to do it, your app will not be accepted in the iTunes store.
Well I have been asked to assess the possibility of such an app that could do just that. Namely my client has seen these two apps
https://itunes.apple.com/us/app/lifesaver-distracted-driving/id874231222?mt=8
https://itunes.apple.com/us/app/at-t-drivemode/id907208943?mt=8
And they are sure that an app, basically exactly like these (based on the functionality) can be made.
So here I am, asking, how did these two apps succeed at the impossible and also how did they manage to get those apps uploaded to the iTunes store, if muting your phone is not an Apple approved option? I am not really asking for source code, although I am certainly not rejecting examples, but moreso I am asking for pointers of what class or book or documentation do I have to look up to figure out if this is possible? Apples CTCall and CT* classes did not seem to help me much.
K

A:

Apple added the CallKit framework in iOS 10 to allow app developers to do this sort of thing, among others.  For docs, see:
https://developer.apple.com/reference/callkit

