In a tweet, HTC’s Vice President of Product Management, Mo Versi, announced that tomorrow, March 31st, the HTC One M7 will be getting Android 5.0 Lollipop.
AT&T HTC One (M7) Owners! Great news, we've received technical approval on Lollipop OS. OTA will start tomorrow. Thank you for your patience
— Mo Versi (@moversi) March 30, 2015
Since this is Android 5.0, it is potentially the last update the HTC One M7 could get, unless HTC changes its mind. So if you have an HTC One M7 on AT&T, you should see the update starting tomorrow.