Despite previous indications, the upcoming Internet Explorer 7 (IE7) will be available for Windows XP Professional x64 Edition and Windows Server 2003 SP1, as well as Windows XP SP2.

When Microsoft chairman Bill Gates unveiled the project two weeks ago at the RSA Conference in San Francisco, he stated that the software would become available for Windows XP only.

The improved version focuses on security enhancements, but Microsoft has given few details about the product's features. A spokesperson for the company declined to comment on features or technologies in IE7 for this article.

However, the browser's development team has shed some light on the software on Microsoft's Internet Explorer blog.

"We currently plan to make IE7 available for Windows XP SP2 and later," said a recent posting. This means that the browser will support both 32-bit and 64-bit versions of Windows.

The blog stopped short of addressing questions about support for Windows 2000 users, although the earlier statements imply that those users will not be able to use the upcoming version because they lack the security enhancements in SP2.

Next to XP, Windows 2000 is the version of the operating system with the highest number of deployments, according to Joe Wilcox, a senior analyst with Jupiter Research.

Microsoft's decision to limit IE7 to Windows versions that have SP2 makes sense, the analyst told vnunet.com.

"Microsoft has already made the decision that the security enhancements [in SP2] would be for XP only. I would expect new features in IE 7 as well, but the foundation is around security," he said.

The move also contradicts the largely held belief that Microsoft is speeding up development of IE7 purely as a response to increased competition from open source browser Firefox. Redmond has always maintained that security concerns are the major factor.

Microsoft has announced that an IE7 beta will be available in mid-2005. A final version will be released "once IE7 meets the quality standards our customers demand", the company said in an email to vnunet.com.

Wilcox expects this to be around the end of 2005 or early next year.