Version 4.4

Release date October 31, 2013

Features

Refreshed interface with white elements instead of blue
Clock no longer shows bold hours; all digits are thin. The H, M, and S markings for the stopwatch and timer have been removed, leaving just the numbers.
Ability for applications to trigger translucency in the navigation and status bars
Ability for applications to use “immersive mode” to keep the navigation and status bars hidden while maintaining user interaction
Action overflow menu buttons are always visible, even on devices with a “Menu” key, which was officially deprecated by Android 4.0.
Restriction for applications when accessing external storage, except for their own directories
Optimizations for performance on devices with lower specifications, including zRAM support and “low RAM” device API
Wireless printing capability
NFC host card emulation, enabling a device to replace smart cards
WebViews now based on Chromium engine (feature parity with Chrome for Android 30)
Expanded functionality for notification listener services
Public API for developing and managing text messaging clients
Storage Access Framework, an API allowing apps to retrieve files in a consistent manner. As part of the framework, a new system file picker allows users to access files from various sources (including those exposed by apps, such as online storage services).
New framework for UI transitions
Sensor batching, step detector and counter APIs
Settings application now makes it possible to select default text messaging and home (launcher) application
Audio tunneling, audio monitoring and loudness enhancer
Built-in screen recording feature (primarily for developers, as usage of ADB is required)
Native infrared blaster API
Verified boot
Enforcing SELinux
Expanded accessibility APIs and system-level closed captioning settings
Android Runtime (ART) introduced as a new experimental application runtime environment, not enabled by default, as a replacement for the Dalvik virtual machine
Bluetooth Message Access Profile (MAP) support
Disabled access to battery statistics by third-party applications
Settings application no longer uses a multi-pane layout on devices with larger screens
Wi-Fi and mobile data activity (TX/RX) indicators are moved to quick settings
Disables text wrapping in the WebView browser component
Camera application now loads Google+ Photos instead of Gallery when swiping away from the camera view
Removal of the “App Ops” application permissions control system, introduced in Android 4.3
Initial release of Android Wear platform for smartwatches: the same as Android 4.4 “KitKat”, but with wearable extensions added
UI updates for Google Maps navigation and alarms
Offline music playback
GPS support