When it comes to software udpates, not all devices are created equal. This boils down to a mix of factors but it always has to do with the OEMs and the carriers that those devices are made for. When it comes to Samsung and the latest version of Android software that's officially available to the public, which at this point is Marshmallow, the Galaxy S6 on AT&T's network has yet to see the version bump from Android Lollipop to Android Marshmallow. Samsung has recently revealed, though, that AT&T's variant of its 2015 flagship smartphone is due to get the software update soon, and will be the next device in its 2015 flagship lineup that receives it. This follows details that the HTC One M8 and One M9 updates to Marshmallow on AT&T's network have been delayed.
With Marshmallow will come a handful of changes and features, including Google's Now On Tap which is likely to be one of the more useful changes to the software once it arrives for AT&T subscribers. Alongside it will be other additions like Doze Mode which is meant to help with battery life, as well as app standby which is also meant to help extend the battery life for the user. More granular permissions control is in tow which will allow users to install apps to their Galaxy S6 and instead of having to grant permissions right then and there, the permissions request will come in once the user opens up the app.
With the Galaxy S6 on the nation's second largest wireless network due to get the update in the near future, the Galaxy S6 Edge is also likely just around the corner, although Samsung hasn't mentioned any details about it just yet. When it comes to the Galaxy S6, they unfortunately haven't given an exact time frame for when the software will begin to hit devices so for now it's still a waiting game. That said, it would appear that some users have already started receiving the software update so the rollout may already be happening to some degree. As always, if you are curious to see whether or not it's available for your own device you can always check manually by heading into settings, about phone, and tapping software updates.