As of Mercurial 1.4.3, the Mercurial license is GPLv2+ and the relicensing process is considered complete.
Matt Mackall and Crew have decided to extend the license of Mercurial from GPLv2 to GPLv2+ by adding the standard "or any later version" clause to the license. Among other things, this will resolve a perceived license conflict involved with Mercurial's SVN conversion code, and allow compatibility with a wider body of free software while maintaining a "strong copyleft".
Because no one person holds the copyright to all of Mercurial's code, this process will require obtaining agreement from the bulk of Mercurial contributors, and possibly replacing or removing any code from other contributors.
- identify all Mercurial contributors from repository history
- find addresses for contributors with unknown addresses
- send form mail to all contributors with known addresses
- collect responses
- follow up with any negative or unresponsive contributors
- if necessary, examine what code we do not have authorization to relicense and determine how to deal with it
From: Matt Mackall <email@example.com> Subject: Response needed from all Mercurial contributors for relicensing To: Mercurial contributors <firstname.lastname@example.org> You're getting this message because you're recorded as contributing one or more changes to the Mercurial project, and are therefore one of many copyright holders in the project. The core development team would like to extend Mercurial's GPLv2 only license to GPLv2+ by adding the recommended "or any later version" clause to the license. This will resolve a license compatibility issue with our SVN conversion tools and give us license compatibility with GPLv3 projects. Please respond to this email with one of the following: YES, I agree to relicense all my contributions to Mercurial to GPLv2+ with the addition of the "or any later version" clause. NO, I would rather not, please send me more email to convince me. Thanks!
See also: http://selenic.com/pipermail/mercurial-devel/2009-October/015963.html by Matt.