Microsoft has released a new build of Windows Server, codenamed Longhorn.

The company posted the release - the December Community Technology Preview (CTP) - of the server OS on its Microsoft Connect site.

Microsoft's CTP program is designed to give users early and frequent updates to forthcoming Microsoft technologies. But only participants of the Longhorn beta program can access the new build, which Microsoft has called 6001.16406.

Longhorn will feature built-in virtualisation technology, as well as better management, security and administration features. The company plans to release the final version of Longhorn in the second half of 2007.