Looks like the October security release and a a few other things. From the AT&T support site:
Release date: November 8, 2016
Android version: 6.0.1
Security patch level (SPL): October 1, 2016
Baseband version: G930AUCS4APJ4
Kernel version: 3.18.20-943921
Build number: MMB29M.G930AUCS4API2
File size: Up to 264MB
The updates:
What's new: Full Screen – Mobile Video Service and Android device security enhancements
What's changing: Improved volume for Enhanced Push To Talk (ePTT) and fix for calls failing to go to Voice Mail when calling non-LTE devices
What's going: Milk Music
Release date: November 8, 2016
Android version: 6.0.1
Security patch level (SPL): October 1, 2016
Baseband version: G930AUCS4APJ4
Kernel version: 3.18.20-943921
Build number: MMB29M.G930AUCS4API2
File size: Up to 264MB
The updates:
What's new: Full Screen – Mobile Video Service and Android device security enhancements
What's changing: Improved volume for Enhanced Push To Talk (ePTT) and fix for calls failing to go to Voice Mail when calling non-LTE devices
What's going: Milk Music