• AT&T Inc. is an American multinational telecommunications corporation, headquartered at Whitacre Tower in downtown Dallas, Texas.

AT&T Inc. is an American multinational telecommunications corporation, headquartered at Whitacre Tower in downtown Dallas, Texas. (Photo : Twitter/AT&T)

Most carriers started rolling out Android 6.0.1 Marshmallow for older smartphones models since last year, except for AT&T. This month, AT&T has finally started rolling out Google's latest mobile operating system to some of its high-end flagship devices such as Samsung Galaxy S6, Galaxy S6 Edge, Galaxy A9, HTC One M9 and One M8.

Like Us on Facebook

It is notable that AT&T has lagged behind the rest of carriers in updating slightly older devices to Android M. Similar models from carriers like Sprint and Verizon have been running on Android 6.0.1 Marshmallow for some time now.

The American multinational telecommunications corporations has only decided to roll out Android 6.0.1 Marshmallow for Samsung Galaxy A9 because the smartphone was only released at the beginning of this year, according to Android Authority. However, Samsung Galaxy S6 and Samsung Galaxy S6 Edge were launched just over one year ago, similar to HTC One M9.

AT&T over-the-air (OTA) update is approximately 1.5 GB for the Galaxy S6 and Galaxy S6 Edge, according to a different report by the same publication. Therefore, users should have their battery more than half-charged, be on an ample, and unmetered Wi-Fi to allow Android M enough time to run through the update process.

Users can check whether there is an OTA Android update ready for their devices by going to Settings > About Phone > System Updates. Updating these devices to Google's latest OS will bring features such as Doze mode and Google Now on Tap, in addition to granular control over apps' permission settings.  

Apparently, Samsung Galaxy A9 will be among the first A series smartphones from the South Korean tech giant to receive the official Android Marshmallow update. The update will roll out for the unlocked model of the device, SM A9000, for the firmware version A9000ZCU1BPE2.

Android N will be the next big thing from Google in the update cycle. The operating system is around the corner, bringing a better Doze mode and baked in VR capability.

However, based on AT&T's update timeline, users on this carrier will possibly have to be patient for one more year before they receive Android N on their devices. Here is a sneak peek for more information: