AT&T's Samsung Galaxy Note 4 and Samsung Galaxy Note Edge are getting updated to Android 5.1.1
The Android 5.1.1 update for the two models also helps improve the performance of the rear camera on each phone, and could include security patches to prevent the Stagefright vulnerability from being used by hackers, to take control of your handset. AT&T hasn't made it clear yet whether the update includes this security protection.
Once you receive notification that the update is ready to be downloaded and installed, you should immediately make sure that you are hooked up to a Wi-Fi network, especially with the size of the files being so huge. Also, make sure that you have your battery charged to at least 50% before you start the updating process.
Because the update is sent out OTA on a staggered basis (it is not yet available to update via Kies), you might not see it hit your Galaxy Note 4 or Galaxy Note Edge for a few days yet. If you are an AT&T customer with either handset, keep your eyes peeled for the notification that it has arrived on your device.