Microsoft introduced Windows Server 2012 and its developer preview in the BUILD 2011 conference on September 9, 2011. However, unlike Windows 8, the developer preview of Windows Server 2012 was only made available to MSDN subscribers. It included a graphical user interface (GUI) based on Metro design language and a new Server Manager, a graphical application used for server management. On February 16, 2012, Microsoft released an update for developer preview build that extended its expiry date from April 8, 2012 to January 15, 2013.