Apple is developing a smart doorbell and lock system that would use Face ID to unlock the door for known residents, according to Mark Gurman.The system would connect to a smart deadbolt, which could include third-party locks or a complete system in collaboration with a lock maker.It is in the early stages of development and likely won't be ready until at least the end of next year.Apple is also working on other smart home products, including a security camera and a smart home hub.