Windows Server 2016 is the eleventh major version of the Windows NT operating system produced by Microsoft to be released under the Windows Server brand name. It was developed alongside Windows 10 and is the successor to the Windows 8.1-based Windows Server 2012 R2. The first early preview version became available on October 1, 2014 together with the first technical preview of System Center. Windows Server 2016 was released on September 26, 2016 at Microsoft's Ignite conference and reached general availability on October 12, 2016.