The AT&T Samsung Galaxy S6 Active is picking up a quick OTA update today. This one brings it from firmware OE9 to OF3, and the changelog isn’t very large.
The biggest change AT&T saw fit to mention was that Find My Mobile now works with Reactivation Mode, so you should be able to use the feature in the event that it gets factory reset. Other than that, there are probably some bugs that were squished which were either not important enough or too numerous to name.
It’s a relatively small download at 146MB, though you’ll probably still want to be on WiFi if your LTE connection isn’t squeaky clean. It’s also always a good idea to have a fairly charged battery.
AT&T notes that this is a mandatory update, and you can postpone installation up to 3 times for up to 8 hours. To grab it all you’ll need to do is head to Settings > About Device > Software Update > Check for Updates.