iOS 10 turns the iPhone's boring Phone app into a software platform in its own right. Developers are now permitted to add previously unheard-of capabilities to Phone using Apple's new application programming interface (API), called CallKit, allowing Voice over IP (VoIP) calls from apps like Skype and WhatsApp to behave like cellular calls.
CallKit-enabled apps put contact images on the Lock screen for incoming VoIP calls and are deeply integrated with Contacts and Phone's Recents and Favorites.
Phone on iOS 10 packs in other exciting improvements that we honestly started to believe would never get implemented on the iOS platform, like voicemail transcription à la Google Voice and third-party extensions for detecting spammy calls automatically.
So let's get to it...