ATT was one of the first carriers to get Android 4.3 for the Samsung Galaxy S4, which meant it was also the first carrier to notice a big issue with the OTA upgrade. The carrier had to suspend rollouts until Samsung got the issue fixed, but they’re starting to roll it back out now that things are all keen and peachy. This upgrade will bring the premium suite features all other 4.3 Samsung devices have gotten, including improved camera features, Samsung Knox security and more.
Alongside all that is also Samsung Galaxy Gear smart watch compatibility. It’s worth noting that the Samsung Galaxy Gear is also getting an upgrade that will improve Smart Relay functionality (seeing a notification on the watch and opening the corresponding notification on your device), as well as the ability to view full notifications for all apps without having to defer to your device. ATT has all the details about what you need to get the upgrade right here, so be sure to check that link out in case you need a bit of help.