AT&T is finally going to begin pushing Marshmallow to both the HTC One M8 and HTC One M9 today according to the Mo Versi, Vice President of Product Management at HTC. despite the fact that the two smartphones’ variants for Verizon, T-Mobile, and Sprint had already received the update.
Android Marshmallow will be available over the air to the AT&T One M9 and One M8 (though it’s possible that not all users will receive the update on the same day). As always, you’ll be able to manually check if the update is available by going to Settings -> About -> Software updates on your device. Be sure to let us know once you start receiving the notifications to update!