Microsoft has revealed that its patent deal with Linspire doesn't cover the new version of the GNU General Public Licence (GPL), the company's latest effort to distance itself from the GPLv3.
In a copy of the Linspire agreement published on Microsoft's website, the company said specifically that the agreement doesn't cover "any portions of products that comprise or include Foundry Products, Clone Products, GPLv3 Software or Other Excluded Products".
Microsoft and Linspire agreed on the deal in mid-June. The agreement, similar to those agreed on by Novell and Xandros, states that Microsoft won't sue Linspire customers for patent infringement.
Microsoft has said that Linux violates 235 Microsoft patents, although it has declined to give further details.
After the Linspire deal was announced, the Free Software Foundation (FSF) released the GPLv3, which aims to make such patent deals legally impossible. The Microsoft document was published on 5 July, following the GPLv3's release.
In theory the exception means that Lindows users could expose themselves to a Microsoft lawsuit if they use open source components licensed under the GPLv3 and those components infringe on Microsoft patents.
Samba, a widely used networking protocol, has said all its future versions will use the GPLv3, and others are expected to migrate to the licence as well.
Microsoft has told shareholders and the public that it believes many popular open source programs infringe on its patents. Critics have argued, however, that there is little evidence to back up such a claim.
The GPLv3 forbids organizations distributing GPLv3-licensed software to form exclusive patent protection agreements with commercial software developers, and prohibits them from suing open source users.