Galaxy S4 Active users in on AT&T, don't get too excited when you see a new software update message appear in your notification bar. This is a minor update with minor changes, and once you apply it the phone will still be running the same Android 4.4.2 build that you've had since June. According to an AT&T support page, the update includes just three things:
Connectivity improvements related to receiving calls and text messaging
Updated Google apps
We've got no idea what kind of updated Google apps Ma Bell put in there, since Google prefers to do its own updating via the Play Store these days. And the company didn't elaborate on the exact nature of the connectivity or security improvements either. If you're running the 4.4.2 update from June, your download should be 127 megabytes. The build number for the new update is KOT49H.I537UCUCNH3.
As always, expect this update to roll out in batches, and don't be surprised if your phone doesn't get it for a few days. Any root or recovery modifications are likely to cause a flash failure for the update, and if you do get it to go through, you might loose root permissions. We don't know when a later version of Android will be available for the GS4 Active, though Samsung has been sending out 4.4.4 for a few carrier devices.