Licenses lie at the heart of open source -- and many other kinds of "open" too. That's because they are used to define the rights of users, and to ensure those rights are passed on -- that the intellectual commons is not enclosed. Their central importance explains in part the flamewars that erupt periodically over which license is "best" -- many people have very strong feelings on the subject.
Those heated discussions are one reason why it's rare for an open source project to change its license -- usually it's just easier to stick with what you've got rather than provoke another argument over which new license should be adopted. But there's another major impediment to changing the licensing: the need to get absolutely everyone who has contributed code to agree formally.
That's not a problem when the code has been assigned by contributors to a single entity, often a software foundation, as happens with components of Richard Stallman's GNU (GNU's Not Unix) project. But the individual copyrights of perhaps the best-known open source code, that of the Linux kernel, have not been assigned in this way. That makes the prospect of contacting the thousands of people who have contributed code, and getting them to agree to a license change, not just hard, but probably impossible, not least because some of them may be dead. For this reason (and because Linus Torvalds doesn't want to change it anyway), Linux is likely to remain licensed under the GNU GPLv2 for the foreseeable future.
Another project where the copyright on code contributions has not been assigned to some central body is the popular multimedia player VLC. Since this is a major project with many hundreds of contributors, you might think it would be similarly impossible to get all of them to agree to a license change. And yet, against the odds, VLC has done just that, thanks to the tireless efforts of Jean-Baptiste Kempf. A fascinating post explains how he achieved this:
The initial license change for libVLC [VLC's main engine] was completed a few months later in December 2011. This involved about 150 developers and 80,000 lines of code. If a developer did not respond to the re-licensing request, that developer's code was rewritten.
But sorting out libVLC was easy compared to the rest of the code:
Then came the task of contacting the authors of the various plug-ins and modules, focusing on the playback modules first. This was a bit more challenging, involving some 300 developers and 300,000 lines of code. Kempf was kind enough to describe his methods for doing so in a few blog posts. He began with details of how to correctly compile the list of names and email addresses and the measures he took to appropriately narrow that list down to remove dupes, people who had already responded in the first relicensing phase, and so forth. His response rate for the initial emails was only 25%, with 25% bouncing and 50% not responding. This had to be frustrating but not entirely surprising. To deal with the remaining 75%, Kempf employed a variety of methods that could be described as stalking or resolutely resourceful, depending on your perspective; social media, the telephone directory, whois lookups, friends or co-workers, and showing up where they work were all fair game.
Impressive stuff, not least because Kempf did manage to get every single person to sign off in the end. Still, as the post quoted above goes on to note, you might think this is an extremely strong argument for using a contributor's assignment that licenses or assigns copyright to some central organization. But VideoLAN, the non-profit group that produces VLC, is located in France, which recognizes the creator's "moral rights", introducing a further complication:
Moral rights include the right of attribution, integrity, disclosure and withdrawal, and are based on the rationale that there exists a personal and inalienable bond between authors and their work. As such, moral rights cannot be assigned or waived.
That means even in the presence of an assignment, authors would still need to give their permission for a license change that would be valid in any country that recognizes moral rights.
The VLC experience confirms that changing a license is not something to be undertaken lightly. But it also shows that with perseverance it can be done -- once the flamewars have subsided, of course.
Follow me @glynmoody on Twitter or identi.ca, and on Google+