While Android 6.0 Marshmallow is getting all the attention, with Google expected to launch the new OS tomorrow, Sept. 29, AT&T has made a last-ditch Android 5.1.1 Lollipop rollout to the Samsung Galaxy S6 and Galaxy S6 Edge units under its network.

The update is now rolling out over the air (OTA). Users who wish to grab the firmware should keep in mind that it weighs 660 MB. Given that, it is recommended to download it via a Wi-Fi connection to avoid data charges.

Those with the Samsung flagships from AT&T who still wait for Android 5.1.1 Lollipop to drop on their handsets can manually check the update's availability by going to Settings -- About Phone -- Software Update. When it shows up, proceed to download.

Android 5.1.1 Lollipop is designed to fix bugs, improve the performance, prolong the battery life and stabilize the Samsung Galaxy S6 and S6 Edge on the whole. A Guest mode and support for the new mobile payment service Android Pay were also integrated.

Users can also expect newly overhauled volume and quick settings, as well as new animations and an enhanced camera app. The update will also make the icons look like the ones on the Samsung Galaxy S5 and will also allow toggling the display of the S Settings and Quick Connect buttons on and off.

While AT&T just dropped Android 5.1.1 Lollipop on the Samsung Galaxy S6 and S6 Edge, NeuroGadget is already reporting that the flagships are already lined up to be updated with the all-new Android 6.0 Marshmallow.

Android users will see the latest iteration of the OS in action tomorrow, as well as the first handsets that will don it, the Nexus 5X and Nexus 6P. It is expected that carriers will take longer to bring the Marshmallow update to the high-end smartphones, although Samsung is said to start on the rollout as early as possible.