Microsoft has announced the first major revision to its Tablet operating system, Windows XP Tablet PC Edition 2005 (code-named Lonestar). The update will be a free upgrade for current Tablet PC owners, and is slated to appear this summer.

Ever since Windows XP Tablet PC Edition debuted in November 2002, Microsoft has insisted that handwriting recognition is not the centrepiece of the operating system's pen-based features. But tweaks to improve the handwriting recognition are the most visible changes in this version.

The new OS will also incorporate Windows XP Service Pack 2 - Microsoft's major security upgrade.