The All New One for AT&T (in silver) was unveiled just minutes ago by @evleaks - which means that we can be almost certain that this is the real deal.
We can see AT&T’s logo on the back of the handset (click on the image for a larger view). That’s the only visible change if we compare this version of the smartphone to the previously revealed ones.
We don’t know when AT&T intends to release the All New HTC One / M8, but we’ll probably hear more on this on March 25, when HTC will officially announce the handset. Feature-wise, the next-gen HTC One should offer (among other things): Android 4.4 KitKat with Sense 6.0 UI, LTE, a twin-sensor rear camera, 4MP front-facing camera, BoomSound speakers, and MicroSD card support.