Microsoft is to meet with representatives from the US Department of Justice (DOJ) next month amidst concerns that the company has not been complying with the anti-trust judgment.

The government said that its technical committee raised concerns about whether Windows XP and Service Pack 2 are in compliance with the judgment, although the company said that it had replied to those concerns recently and the government is reviewing its responses.

The developments are outlined in a joint status report filed by Microsoft and the DOJ on the software maker's progress in complying with the judgement, approved in November 2002. Among the requirements, Microsoft has to make it easy for customers to use non-Microsoft middleware products with its operating systems, including Web browsers and media players. The goal is to prevent Microsoft from using the ubiquity of Windows to lock rivals out of the market.

The government already said it was talking to Microsoft about ensuring Longhorn's compliance with the measures. In its status report Tuesday the DOJ said the first meeting with Microsoft is scheduled for mid-February, when its scrutiny of Longhorn will "begin in earnest." The desktop version of Longhorn is expected in 2006 and the server version in 2007.

The DOJ also completed its analysis of Windows XP and Service Pack 2, which involved running hundreds of tests to check how the operating system behaves in relation to third-party middleware products.

"The work has identified several circumstances in which further information from Microsoft is needed to determine whether Windows satisfactorily honors user middleware choices," the government wrote. It did not provide specifics.

The 2002 judgment also required Microsoft to document and license Windows communications protocols to make it easier for vendors to develop products that work with its operating system. The government has complained that Microsoft was behind schedule with the work, and also chided it for releasing the documents in a format that can't be annotated and only work with Internet Explorer.

Microsoft has now agreed to release the documents in Adobe Systems's PDF (Portable Document Format) by the end of June, according to the latest status report. The parties also developed a new, two-part plan for ensuring the documents are complete and accurate -- although it will take up to a year to complete: The government's technical committee will develop a prototype implementation of each task covered by the protocols, and Microsoft will release a network parsing tool to help companies that have licensed the protocols develop products.

Microsoft said that complying with the judgment continues to be an important priority for the company.

"While issues inevitably will arise, Microsoft has worked diligently and cooperatively to respond to and resolve all inquiries from plaintiffs," its lawyers wrote.

Critics have charged that the judgment against Microsoft did not go far enough to rein in the power of its monopoly or penalise it for its past ills, and several US states had been pushing for stiffer penalties. The EU has since enforced tougher sanctions, including a requirement that Microsoft sell a version of Windows in Europe without its Windows Media Player and license additional communications protocols.