AT&T has released a new software update G920AUCU6EQK3 for Galaxy S6 and update G925VVRS4DQK1 for Galaxy S6 Edge smartphone. Galaxy S6 Active is also receiving update G890AUCU6DQK3. The latest patch is rolling out with Android December Security patch and the BlueBorne exploit fix.
Android December Security patch addresses Common Vulnerabilities and Exposures (CVE) in the open-source Android OS. Additionally, there are improvements in network performance. The update also adds support for new Mobile Hotspot APN.
Software update G920AUCU6EQK3 for Galaxy S6 and update G925VVRS4DQK1 for Galaxy S6 Edge will gradually release to everyone. You can also check manually for updates, go to Settings > About device > System update.
Make sure you have enough charge on your device at least 60% to 70% before downloading the update.