So, the regular Galaxy S5 is finally starting to get an update to Android 5.0, and what's this? The GS5 Active on AT&T is getting an update. Could it be? Is this the moment we've been waiting for? Oh... nope. It's just Android 4.4.4.
Here's the changelog. As you can see, it's highly descriptive.
- Android KitKat 4.4.4
- Miscellaneous improvements, bug fixes, and security updates
You can head into the update menu to manually pull the OTA, otherwise it will show up in a few days. The update is mandatory, and will eventually force installation after you've postponed a few times. Don't want Samsung's crummy KitKat update? Tough.
- Samsung Support