There is no official change-log available but as per SamMobile, the changes are pretty much same as the Snapdragon version apart from the lack of OpenGL 3.0 support. You can check out the full list of changes below.
- TRIM Support
- ANT+ Support
- Samsung KNOX Implementation
- Pre-loaded Samsung Wallet
- Improved RAM management
- Improved Display colour reproduction
- Improved TouchWiz Launcher
- New Samsung Keyboard
- New Samsung Browser
- New Reading Mode
- New Camera firmware
- Minor UI tweaks (Contacts app, Flashlight Widget, dialog boxes etc)
The update is being rolled-out in phases, so not everyone will get it right away. To manually check for the update, connect your Galaxy S4 to your computer and open Kies or go to Settings > More > About Device > Software update > Update on your phone.
