objective c - Can an iPhone app block phone calls?

Question

Is it possible to write an application that will block incoming and outcoming phone calls? Or is the iPhone locked down too much? Thanks!

Answer 1

EDIT: See Rajan Maheshwari's answer below. CallKit now provides this. Even things that seemed they would never change, can change eventually.

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Anything that modifies a user's ability to make or receive phone calls is going to run afoul of Apple's basic approach to third-party apps. There are a lot of things that are questionable and you might get away with. Blocking calls is clearly forbidden.