CallKit issues reportedly force Apple to put some call-directory extensions reviews and approvals on hold
If you’ve tried any of the call blockers, or spam identifiers in iOS 10, you’ve surely been disappointed. I’ve tested out a number of them and they really haven’t seemed to do anything at all. Most of the time not blocking, or even identifying calls. It appears we may now know why.
It looks to be an underlying issue with CallKit, Apple’s new framework that powers these types of apps.