Free Software Foundation Explains GPL 3.0 Vision

DRM (Digital Rights Management) is another threat to free software, they said, as DRM is fundamentally at odds with the spirit of the free software movement.

"Unfree software implementing DRM technology is simply a prison in which users can be put to deprive them of the rights that the law would otherwise allow them. Our aim is, and must be, the abolition of DRM as a social practice. Anything less than complete victory leaves the freedom of software in grave peril," they said.

Even as companies imposing DRM prohibit access to digitally restricted data by users, they often try to turn free software into tools of user restriction, Stallman and Moglen wrote, adding, "We must not tolerate this assault on users freedom merely because the software used for this assault is a version of our own. The GPLv3 has been designed to forbid such perversion of free software."

The ability to oppose DRM by means of free software licenses has been limited, but the new license does provide developers with some forms of leverage that they can use against DRM. The new provisions essentially direct the courts to interpret the GPL in light of a policy of discouraging and impeding DRM and other technical restrictions on users freedoms and illegal invasions of privacy.

"This provides copyright holders and other GPL licensors with means to take action against activities contrary to users freedom, if governments fail to act. If a covered work is distributed as part of a system for generating or accessing certain data, the effect of this license is to prevent someone from claiming that some other GPLd program that accesses the same data is an illegal circumvention," Moglen and Stallman said.

Another challenge facing the free software community is the proliferation of incompatible free software licenses, they said.

While the goal was not to make the GPL compatible with all such licenses, Version 3 contains provisions designed to reduce license incompatibility by making it easier for developers to combine code carrying non-GPL terms with GPL code.

"It is important that the GNU GPL enable business to succeed while respecting freedom, and we do not intend to interfere with the synergy between them," Stallman and Moglen wrote.

GPLv3 takes a new approach to the issue of combining GPL code with code governed by the terms of other free software licenses.

"Our view, though it was not explicitly stated in GPLv2 itself, was that GPLv2 allowed such combinations only if the non-GPL licensing terms permitted distribution under the GPL and imposed no restrictions on the code that were not also imposed by the GPL," the rationale document said.

The OSI recognizes open-source license proliferation as an obstacle to deployment. Click here to read more.

In practice, this policy was supplemented with a structure of exceptions for certain kinds of combinations. Version 3 formalizes the circumstances under which a licensee could release a covered work that includes an added part carrying non-GPL terms. <>It distinguishes between terms that provide additional permissions, and terms that place additional requirements on the code, relative to the permissions and requirements established by applying the GPL to the code.

"It explicitly allows added parts covered by terms with additional permissions to be combined with GPLd code. This codifies our existing practice of regarding such licensing terms as compatible with the GPL. A downstream user of a combined GPLd work who modifies such an added part may remove the additional permissions, in which case the broader permissions no longer apply to the modified version, and only the terms of the GPL apply to it," the authors said.

For those terms that impose additional requirements, this version extends the range of licensing terms with which the GPL is compatible. An added part carrying additional requirements may be combined with GPLd code, but only if those requirements belong to a set enumerated in the license.

"Unlike terms that grant additional permissions, terms that impose additional requirements cannot be removed by a downstream user of the combined GPLd work, because no such user would have the right to do so," they said.

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