Samsung is currently working on Android 4.4.2 KitKat Update for its Galaxy S4 smartphone. But before the official announcement, the pre-release firmware has been leaked on the Internet. This leaked version is stable enough that anyone can use it on their Galaxy S4 smartphone. The KitKat Update will bring an enhanced lockscreen with a camera shortcut on the lower right corner, increase in the benchmark scores, improved keyboard and more.
This update is only compatible with GT-I9505 Snapdragon 600 variant of Galaxy S4. Those who are having the Exynos 5 Octa model will have to wait a bit more. You can download the required file from here and flash it on your Galaxy S4 smartphone.