The first country to obtain the update is Germany, but other regions will allegedly be joining the whitelist shortly. German Samsung World S4 clients can update both OTA or using the Samsung Kies software packages.
The Android 4.3 update brings numerous abilities, although many of them are people of Samsung's proprietary TouchWiz UI launcher as opposed to the OS itself.
This can be truly the entire changelog for the update as develop with SamMobile:
- OpenGL 3.0 Support
- GALAXY GEAR Support
- TRIM Support (Makes the device much faster)
- ANT+ Support
- vSamsung KNOX Implementation (KNOX bootloader and dedicated application)
- Samsung Wallet comes pre-loaded
- Improved RAM management
- Improved Display colour reproduction (Display looks much sharper than before)
- Improved TouchWiz Launcher (Much less launcher redraws and less lag)
- New Samsung Keyboard
- New Samsung Browser (Full screen by default, new tab interface and more)
- New Reading Mode (Optimises display for reading, used by only a few specific applications)
- New Camera firmware
- Minor UI tweaks (Contacts app, Flashlight Widget, dialog boxes etc)
To update your Galaxy S4 to Android 4.3 Jelly Bean, connect your device to your computer and use Samsung KIES or simply use Samsung's OTA service. To download and install the firmware via OTA, go to Settings > More > About Device > Software update > Update.