It has been a long wait for Samsung Galaxy S6 users on AT&T, but not any more. The Galaxy S6 Android 6.0 Marshmallow update has been released by the mobile carrier and is now available to download. The information has been confirmed by a support page on the official Samsung website that claims that the Galaxy S6 on AT&T is now receiving the Marshmallow OTA update.
The Android 6.0.1 Marshmallow update for the Samsung Galaxy S6 on AT&T comes with build number G920AUCU3CPC2 and brings all the latest Marshmallow features like the new Doze mode that saves power significantly, new app permissions, and Google Now on Tap. The information about the new update hasn’t been put out on the AT&T website yet.
As always, the Marshmallow update is a large one and might be around 800MB-1GB in size. So make sure that you are connected to a speedy WiFi network before you start downloading the update. Also charge your phone completely to avoid the battery from running out during the update. In case you have not received the update notification yet, you can check for the update manually by going to Settings > System tab > About device > Software update > Check for updates.