Free Software, Free Society: selected essays of Richard M. Stallman. 2nd edition.

GPLv3 also provides users with explicit patent protection from the program’s contributors and redistributors. With GPLv2, users rely on an implicit patent license to make sure that the company which provided them a copy won’t sue them, or the people they redistribute copies to, for patent infringement.

The explicit patent license in GPLv3 does not go as far as we might have liked. Ideally, we would make everyone who redistributes GPL-covered code give up all software patents, along with everyone who does not redistribute GPL-covered code, because there should be no software patents. Software patents are a vicious and absurd system that puts all software developers in danger of being sued by companies they have never heard of, as well as by all the megacorporations in the field. Large programs typically combine thousands of ideas, so it is no surprise if they implement ideas covered by hundreds of patents. Megacorporations collect thousands of patents, and use those patents to bully smaller developers. Patents already obstruct free software development.

The only way to make software development safe is to abolish software patents, and we aim to achieve this some day. But we cannot do this through a software license. Any program, free or not, can be killed by a software patent in the hands of an unrelated party, and the program’s license cannot prevent that. Only court decisions or changes in patent law can make software development safe from patents. If we tried to do this with GPLv3, it would fail.

Therefore, GPLv3 seeks to limit and channel the danger. In particular, we have tried to save free software from a fate worse than death: to be made effectively proprietary, through patents. The explicit patent license of GPLv3 makes sure companies that use the GPL to give users the four freedoms cannot turn around and use their patents to tell some users, “That doesn’t include you.” It also stops them from colluding with other patent holders to do this.

Further advantages of GPLv3 include better internationalization, gentler termination, support for BitTorrent, and compatibility with the Apache license. All in all, plenty of reason to upgrade.

Change is unlikely to cease once GPLv3 is released. If new threats to users’ freedom develop, we will have to develop GPL version 4. It is important to make sure that programs will have no trouble upgrading to GPLv4 if and when we write one.

One way to do this is to release a program under “GPL version 3 or any later version.” Another way is for all the contributors to a program to state a proxy who can decide on upgrading to future GPL versions. The third way is for all the contributors to assign copyright to one designated copyright holder, who will be in a position to upgrade the license version. One way or another, programs should provide this flexibility for future GPL versions.

Copyright c 2007, 2009 Richard Stallman

This essay was originally published on http://gnu.org, in 2007. This version is part of Free Software, Free Society: Selected Essays of Richard M. Stallman, 2nd ed. (Boston: GNU Press, 2010).

Verbatim copying and distribution of this entire chapter are permitted worldwide, without royalty, in any medium, provided this notice is preserved.

Chapter 30. The GNU Lesser General Public License

Version 3, 29 June 2007

Copyright c 2007 Free Software Foundation, Inc. http://fsf.org/

Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

This version of the GNU Lesser General Public License incorporates the terms and conditions of version 3 of the GNU General Public License, supplemented by the additional permissions listed below.

0. Additional Definitions.

As used herein, “this License” refers to version 3 of the GNU Lesser General Public License, and the “GNU GPL” refers to version 3 of the GNU General Public License.

“The Library” refers to a covered work governed by this License, other than an Application or a Combined Work as defined below.

An “Application” is any work that makes use of an interface provided by the Library, but which is not otherwise based on the Library. Defining a subclass of a class defined by the Library is deemed a mode of using an interface provided by the Library.