When HTC announced its newest Desire EYE smartphone with the camera-focused Eye Experience, it promised that those features will soon find their way to older devices like the M7 and M8. And sure enough, the One M8 in Europe started getting the update the very next day. It's now the unlocked Developer Edition's turn, as an OTA to version 3.28.1540.5 is starting to hit some users.
The update bumps the Android version to KitKat 4.4.4 and brings the entire suite of HTC's new photography tools to the phone, including Auto Selfie, Face Tracking, Split Capture, Live Makeup, and Face Fusion. If you still have no idea what these marketing buzz terms mean, you should check out HTC's 5 video tutorials that demo them in fun (and sometimes weird) conditions.
As with any OTA update, you should check your phone to see if it's ready for you, but don't panic if it isn't. It may be rolling out in batches.