Microsoft's brawl with TomTom over FAT patents has been seized on by software-freedom advocates as a wake-up call for people to adopt GPLv3.
Open-source developers can protect themselves, their customers and the cause of software freedom in general by switching code currently under GPLv2 to the updated GPLv3, the Software Freedom Law Center has said.
GPLv3 will close potential gaps in the wording of the GPLv2 that the SFLC believes Microsoft has exploited in order to tie up a patent cross-licensing deal with TomTom.
The organization believes Microsoft's been using this uncertainty to also tie off other deals with a string of open-source users, starting with Novell in 2005.
Under such deals, it seems, Microsoft has accorded to assignees and their customers a commitment not to prosecute for claimed violations of its patents in Linux and open source.
SFLC policy analyst Bradley Kuhn said Thursday Microsoft has managed to convince companies that patent protection covenants are compatible with the GPLv2. "Since most of them are about the kernel named Linux, and the Linux copyright holders are the only ones with power to enforce, Microsoft is winning on this front," Kuhn blogged.
But because the terms of deals and covenants are not made publicly available it's impossible to know whether Microsoft's patents claims are legitimate and have been upheld, or how far the patent protection clause extends to other users of the open-source software.
This helps maintain the state of uncertainty, and allows Microsoft to keep signing off deals potentially boxing in free software in general, and GPL'd code in particular.
"According to Microsoft and TomTom, the agreement gives some sort of 'patent protection' to TomTom customers, and presumably no one else. This means that if someone buys a GNU/Linux-based TomTom product, they have greater protection from Microsoft's patents than if they don't," Khun wrote.
"It creates two unequal classes of users: those who pay TomTom and those who don't. The ones who don't pay TomTom will have to worry if they will be the next ones sued or attacked in some other way by Microsoft over patent infringement."
Moving to GPLv3 removes any ambiguity, and the ability for Microsoft to come knocking, because the patent license you grant in your software is extended to all recipients of that software or recipients of works that are based on that software. ®