Microsoft is continuing its cat-and-mouse game with anti-trust regulators, extending a licensing program at the same time as the US Department of Justice (DoJ) says the documentation released by the software giant is "unusable".

In filings placed the same day, Microsoft said its MCPP licensing program would now cover use of the protocols for certain server-to-server and server-to-non Windows client communications (although, of course, it failed to say which ones - could it be only these schemas?); and the DoJ said that "the technical documentation needs substantial revision in order to ensure that is usable by licensees".

The filings are a joint status report on Microsoft's adherence to the final judgment in the DoJ's anti-trust case made in 2002. As part of the court's requirements, Microsoft had to make the protocols available to third parties on reasonable, non-discriminatory terms. Microsoft started licensing the protocols in August 2002, and the program has been revised several times since then in response to criticisms by the DoJ.

The MCPP has been called a failure for only attracting 11 companies, although a further three have signed up since the start of the year - Time Warner, Sun and GeoTrust. The technical documentation provided by Microsoft has been widely complained about and Microsoft has promised to make over 5,000 pages of technical info less complex.

The software giant was also forced to pull out so-called "non-assert provisions" which prevented licensees from suing Microsoft over patents related to Windows. Nevertheless, only Massachusetts has so far refused to accept the final judgment and continues to push for tougher remedies.

A status conference on Microsoft's compliance has been set for 21 April.