Android Jelly Bean is the name given to three versions of Android mobile operating system developed by Google and launched between June 2012 to July 2013. The versions include 4.1, 4.2, 4.3.1. 4.1, was unveiled at Google's I/O developer conference in June 2012, focusing on performance improvements designed to give the operating system a smoother and more responsive feel, improvements to the notification system allowing for "expandable" notifications with action buttons, and other internal changes. 4.2 included further optimizations, multi-user support for tablets, lock screen widgets, quick settings, and screen savers, and 4.3 contained further improvements and updates to the underlying Android platform. As on Feb 2015, 40% of the android devices are running on one of the Jelly Bean versions.