The maintainers of the Mozilla Public License are excited to announce the release of version 2.0 of the Mozilla Public License (html, txt). We hope that this license will serve its users well for the next decade, just as MPL 1.1 did.
About the MPL
Just like version 1.1, version 2.0 of the Mozilla Public License is a “file-level copyleft” license. The license is designed to encourage contributors to share modifications they make to MPL-licensed code, while still allowing users to create projects that combine MPL-licensed code with code under other licenses (either open or proprietary).
MPL 2.0, like MPL 1.1 before it, has been approved as a free software license by the Free Software Foundation, and as an Open Source license by the Open Source Initiative.
What’s New
The result of a two year revision process that included feedback and suggestions from the Mozilla community, users of the MPL (both community and corporate), and the broader open source legal community, MPL 2.0 contains several important changes from MPL 1.1. In particular, MPL 2.0:
- is simpler and shorter, using the past 10 years of in-practice application of the license to help better understand what is and isn’t necessary in an open source license.
- is modernized for recent changes in copyright law, and incorporates feedback from lawyers outside the United States on issues of applicability in non-US jurisdictions.
- provides patent protections for contributors more in line with those of other open source licenses, and allows an entire community of contributors to protect any contributor if they are sued.
- provides compatibility with the Apache and GPL licenses, making code reuse and redistribution easier.
For a more complete list of changes, see the FAQ’s entry on “what has changed.”
Using MPL 2.0
The MPL FAQ explains how to use MPL 2.0 for new code, and the MPL Revision FAQ explains how to use MPL 2.0 for code originally licensed under MPL 1.1.
The Mozilla Project has announced that it will move to the new license. Further plans and procedures for moving to MPL will be announced on appropriate newsgroups, including mozilla-governance.
Other Materials
Along with the release of MPL 2.0, we have released a variety of materials designed to help answer questions about the new license.
- FAQ: The MPL FAQ answers critical questions about the license. We will continue to revise and update this as new questions are asked.
- Revision Process FAQ: The Revision Process FAQ answers questions about the process we followed to upgrade the license from 1.1 to 2.0, including details on the changes made to the license.
- Historical Information: We’ve collected a variety of historical information about previous versions of the license, including old license texts and license FAQs, in one place, for reference.
Acknowledgements
Any two-year long process will necessarily involve feedback and involvement from too many people to thank completely in one place. With apologies to those we have overlooked, the maintainer and peers would like to thank the following people, who have been particularly helpful in various areas:
- Members of the mozilla-governance-mpl newsgroup, particularly including Benoit Jacob, Ben Bucksch, Alexis Richardson, and Michael Kay. Many of this group’s suggestions made it into the license, but even when the suggestions couldn’t be incorporated, they pushed to make the license better.
- Heather Meeker and Karen Copenhaver, who both contributed a substantial amount of time and expertise, particularly during the critical beta period when much wordsmithing was necessary.
- Till Jaeger, who was instrumental in helping us think through international copyright issues.
- Daniel German and other members of his research group, whose useful advice and research helped us understand how licenses are deployed in the wild.
- Brett Smith, Eben Moglen, Aaron Williamson, James Vasile, and Richard Fontana, who all gave helpful feedback in many areas, but particularly in the area of GPL compatibility.
- Simon Phipps, Karl Fogel, and OSI’s license-review list, who were all very helpful in shepherding the license through the OSI process.
- The fine folks in Apache’s legal team, who were helpful in discussing Apache compatibility issues early in the process.
- Members of the FSFE’s FSFE Legal team, as well as many other in-house lawyers from several large software firms who preferred not to be named publicly but quietly gave their time and specific advice to help improve the license.
- The creators of the open source software tools used to write the license, particularly the co-ment team, G.P. Halkes of dwdiff, and John MacFarlane of pandoc.
Contacting Us
If you have any questions about the new MPL, please contact licensing@mozilla.org.
– the maintainer and peers (Mitchell Baker, Harvey Anderson, Gervase Markham, Heather Meeker, and Luis Villa)