Symbian is a mobile operating system (OS) and computing platform designed for smartphones and currently maintained by Nokia. The Symbian platform is the successor to Symbian OS and Nokia Series 60; unlike Symbian OS, which needed an additional user interface system, Symbian includes a user interface component based on S60 5th Edition. The latest version, Symbian^3, was officially released in Q4 2010, first used in the Nokia N8.
Symbian OS was originally developed by Symbian Ltd. It is a descendant of Psion’s EPOC and runs exclusively on ARM processors, although an unreleased x86 port existed.
Some estimates indicate that the cumulative number of mobile devices shipped with the Symbian OS up to the end of Q2 2010 is 385 million.
By April 5, 2011, Nokia released Symbian under a new license and converted to a proprietary shared-source model as opposed to an open source project.
On February 11, 2011, Nokia announced that it would migrate away from Symbian to Windows Phone 7. In June 22, 2011 Nokia has made an agreement with Accenture as an outsourcing program. Accenture will provide Symbian based software development and support services to Nokia through 2016 and about 2,800 Nokia employees will be Accenture employees at early October 2011.