HomeKit is Apple's upcoming framework for smart home devices such as lightbulbs, door locks, garage door openers, and thermostats. Many of these devices will connect directly to users' iPhones via Bluetooth or Wi-Fi--no separate hub device required--for unified voice control through Siri. They'll also be able to connect with an Apple TV, allowing for Siri voice controls when users are away from home.
Apple will also let users connect devices that aren't approved under the the Made for iPhone (MFi) program, using a separate bridge device that hooks them into HomeKit. This will allow companies like Insteon to make their existing range of smart home devices compatible with Apple's framework, even if they use alternative networking protocols such as ZigBee or Z-Wave.
But according to 9to5Mac's sources, these non-MFi devices won't have the same capabilities as products built with HomeKit in mind. Here's how they'll reportedly work:
A device that doesn't work with HomeKit isn't useless, of course; it just means you can't control it in a unified manner with your HomeKit devices using Siri.
Why this matters: Simplicity and security are major obstacles in the way of smart home acceptance, and that seems to be what Apple is targeting with these rules. As 9to5Mac points out, Apple won't allow bridged devices to trigger door locks or other products that provide physical access to the house, possibly because they represent a weak spot in smart home networks. Bridges also add complexity, so it's no surprise that Apple is looking to discourage their use and steer people toward simpler Wi-Fi and Bluetooth-based setups.