Both phones are getting the KitKat update over-the-air and your phone will automatically notify you once the update is available.
Talking about Galaxy S4 Active update first (447MB – 877MB in size, depending on your phone OS version), here is the full change-log:
- Improved user interface with Android 4.4 KitKat: Includes re-styled status and navigation bars, a new full-screen-immersive mode, color emoji support, improved closed captioning support, stronger security and smarter power use.
- Full screen album art and media controls on lock screen
- Camera icon on the lock screen
- Integrated location menu
- Cloud-print support
- New sound controls
- Improved phone dialer, camera, and gallery apps
To manually check for the update on Galaxy S4 Active, go to About Device > Select Software Update > Select Check for Updates.
Coming to LG G Flex update (686 MB in size), check out the official change-log below, it includes mostly the KitKat specific changes.
- New full-screen mode
- Restyled status and navigation bars
- Battery performance improvements
- Enhanced processing speed
To manually check the update on G Flex, go to Settings > General tab > About phone > Software update > Update now.
