A Windows Phone update is being pushed out for the AT&T HTC 8X but there's not much to go on as far as what the update accomplishes.
The OS version remains at 8.0.10211.204 and the Firmware reads 1532.20.20100.502. The update only takes a few minutes to install and there isn't anything obvious as to what the update brings to the table.
Our guess is this update is similar to the update Verizon pushed out recently and has a few patches here, a few fixes there. We'll see what we can dig up but in the meantime, if you see any changes after updating, let us know below in the comments.