As well as killing off the headphone jack, Apple has dropped the mechanical home button from the new iPhone 7, replacing it with a static version that's force sensitive. Instead of a button that physically moves, the new home button will use Apple's "taptic engine" to click back at users. Vibrations delivered through the home button will be used as notifications, with unique buzzes for things like text messages and calls. Third-party companies will also be able to program their own feedback through a taptic engine API.
Here's what The Verge's Dieter Bohn had to say about the new home button after trying out the iPhone 7:
Another thing I tried: the new home button, which uses a "taptic engine" to give you physical feedback when you press it — it's pressure sensitive, too, so it can tell if you really mean to press it or just tap it. And it's awful. On a MacBook trackpad, you get this uncanny feeling that you're actually hitting a button. On the iPhone, the whole bottom of the phone just sort of "kicks." It's not bad haptics like you remember, with weird vibration, it's just a new kind of bad haptics. It doesn't feel like a button at all. It's a bummer.
This isn't the first time Apple has dropped a mechanical part in favor of a digitized version, of course. The click wheel on the iPod started out as a moving part in 2001, before being replaced the following year with a capacitive version. Eventually, of course, the click wheel was phased out altogether in favor of a single display, and it's possible that the same will happen here. Getting rid of mechanical parts means less breakages and allows Apple to create a sealed enclosure — necessary to make the iPhone 7 water resistant. This might be the last stand for an iconic piece of iPhone design, though, as we've heard rumors that next year's models won't have a home button at all.