Here goes the update details:

- What's New: Android device security updates
AT&T Galaxy S7 SM-G930A Update version G930AUCS4BQE1
- Android version: 7.0
- Android Security patch level: May 1, 2017
- Baseband version: G930AUCS4BQE1
- Kernel version: 3.18.31-11198144
- Build number: NRD90M.G930AUCS4BQE1
- Previous version required: G930AUCU4BQD4
AT&T Galaxy S7 edge SM-G935A Update version G935AUCS4BQE1
- Android version: 7.0
- Android Security patch level: May 1, 2017
- Baseband version: G935AUCS4BQE1
- Kernel version: 3.18.31-11198144
- Build number: NRD90M.G935AUCS4BQE1
- Previous version required: G935AUCU4BQD4
AT&T Galaxy S7 active SM-G935A Update version G891AUCS2BQE1
- Android version: 7.0
- Android Security patch level: May 1, 2017
- Baseband version: G891AUCS2BQE1
- Kernel version: 3.18.31-10651105
- Build number: NRD90M.G891AUCS2BQE1
- Previous version required: G891AUCS2BQD4
How to update Galaxy S7 or a Galaxy S7 edge via Over-The-Air:
Ensure your device battery is fully recharged before starting the software update. This is a must and very important part to get rid of some issues if ever the software update being interrupted due to a power failure.
- From the Home screen, tap the Menu Key > Settings > About device > Software updates > Check for Updates.
- If your device finds a new software update, tap Download now. When complete, a screen will appear advising you that the new version of software is ready to be installed. Tap Install update.
- The device will power down and power back on. A screen will appear stating that the installation has been completed. Tap OK.
- You’ve successfully updated your Galaxy S7 and S7 edge Android OS.
[Thank’s Sarah]
source: AT&T Galaxy S7 (here) and Galaxy S7 edge (here)