Windows Server 2003 is a server operating system produced by Microsoft. Introduced as the successor to Windows 2000 Server, it is considered by Microsoft to be the cornerstone of its Windows Server System line of business server products. An updated version, Windows Server 2003 R2, was released to manufacturing on 6 December 2005. According to Microsoft, Windows Server 2003 is more scalable and delivers better performance than its predecessor, Windows 2000. Its successor, Windows Server 2008, was released on 4 February 2008.