Android 4.4 KitKat is a version of the Android operating system released by Google in October 2013. It introduced a more streamlined user interface, improved performance, and better memory management, making it suitable for devices with lower specifications. The update also featured a new immersive mode for apps, allowing users to enjoy content without distractions. Additionally, KitKat brought enhancements to voice recognition and introduced the Google Now feature, which provided users with personalized information based on their habits. It also included support for NFC payments and improved the overall security of the system, making it a significant update in the Android ecosystem.