Software relicensing

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Software relicensing is applied in open-source software development when software licenses of software modules are incompatible and are required to be compatible for a greater combined work. Licenses applied to software as copyrightable works, in source code as binary form, [1] can contain contradictory clauses. These requirements can make it impossible to combine source code or content of several software works to create a new combined one. [2] [3]

Contents

Motivation and description

Sometimes open-source software projects get stuck in a license incompatibility situation. Often the only feasible way to resolve this situation is re-licensing of all participating software parts. For successful relicensing the agreement of all involved copyright holders, typically the developers, to a changed license is required. While in the free and open-source domain achieving 100% coverage of all authors is often impossible due to the many contributors involved, often it is assumed that a great majority is sufficient. For instance, Mozilla assumed an author coverage of 95% to be sufficient. [4] Others in the free and open-source software (FOSS) domain, such as Eric S. Raymond, came to different conclusions regarding the requirements for relicensing of a whole code base. [5]

Cases

An early example of an open-source project that did successfully re-license for license compatibility reasons is the Mozilla project and their Firefox browser. The source code of Netscape's Communicator 4.0 browser was originally released in 1998 under the Netscape Public License/Mozilla Public License [6] but was criticised by the FSF and OSI for being incompatible. [7] [8] Around 2001 Time Warner, exercising its rights under the Netscape Public License, and at the request of the Mozilla Foundation, relicensed [9] all code in Mozilla that was under the Netscape Public License (including code by other contributors) to an MPL 1.1/GPL 2.0/LGPL 2.1 tri-license, thus achieving GPL-compatibility. [10]

The Vorbis library was originally licensed as LGPL, but in 2001 the license was changed to the BSD license with endorsement of Richard Stallman to encourage adoption. [11] [12]

The VLC project also has a complicated license history due to license compatibility: in 2007 it decided for license compatibility reasons to not upgrade to the just released GPLv3. [13] After the VLC was removed from Apple App Store at the beginning of 2011, in October 2011 the VLC project re-licensed the VLC library part from the GPLv2 to the LGPLv2 to achieve better compatibility. [14] [15] In July 2013 the VLC application could then be resubmitted to the iOS App Store relicensed under the Mozilla Public License. [16]

7-Zip's LZMA SDK, originally dual-licensed under both the GNU LGPL and Common Public License, [17] with an additional special exception for linked binaries, was placed by Igor Pavlov in the public domain on December 2, 2008. [18]

The GNU TLS project adopted the LGPLv3 license in 2011 but in 2013 relicensed their code back to LGPLv2.1 due to serious license compatibility problems. [19] [20] [21]

The GNU Free Documentation License in version 1.2 is not compatible with the widely used Creative Commons Attribution-ShareAlike license, which was a problem, for instance, for the Wikipedia. [22] Therefore, at the request of the Wikimedia Foundation, the FSF added, with version 1.3 of the GFDL, a time-limited section allowing specific types of websites using the GFDL to additionally offer their work under the CC BY-SA license. [23] Following in June 2009, the Wikimedia Foundation migrated their projects (Wikipedia, etc.) by dual licensing to the Creative Commons Attribution-ShareAlike as main license, additional to the previously used GFDL. [24] An improved license compatibility with the greater free content ecosystem was given as reason for the license change. [25] [26]

In 2010 the OGRE project changed their license from the LGPL to the MIT License; a simpler license text was given as reason. [27] [28] [29]

Another case was the relicensing of GPLv2 licensed Linux kernel header files to the BSD license by Google for their Android library Bionic. To get rid of the GPL, Google claimed that the header files were cleaned from any copyright-able work, reducing them to non-copyrightable "facts". [30] [31] This interpretation was challenged for instance by Raymond Nimmer, a law professor at the University of Houston Law Center. [32]

In November 2013 POV-Ray was relicensed under the Affero General Public License version 3 (or later), [33] after being distributed since 1991 under a FOSS-incompatible, non-commercial source available custom POV-Ray license. [34] [35] POV-Ray was developed before FOSS licenses became widely used, therefore the developers wrote their own license which became later a problem due to license incompatibility with the FOSS ecosystem.

In 2014 the FreeCAD project changed their license from GPL to LGPLv2 due to GPLv3/GPLv2 incompatibilities. [36] [37]

In 2014 Gang Garrison 2 relicensed from GPLv3 to MPL for improved library compatibility. [38] [39]

In May 2015 the Dolphin project changed its license from "GPLv2 only" to "GPLv2 or any later" for better compatibility. [40]

In June 2015 mpv started the relicensation process of the project's GPL licensed source code for improved license compatibility under LGPLv2 by getting consent from the majority (95%+) of the contributing developers. [41] In August 2016 approx. 90% of the authors could be reached and consented. In October 2017 the switch was finalized. [42]

In July 2015 Seafile switched for improved license compatibility, especially with Git, from the GPLv3 to the GPLv2. [43] [44]

In 2015 Natron was relicensed from MPL to the GPLv2 to allow better commercialization. [45]

In 2016 MAME achieved a relicensing of the code base to BSD/GPL [46] after struggling for years with an own written custom license, with non-commercial license terms. [47] [48] [49] [50]

In August 2016 the MariaDB Corporation relicensed the database proxy server MaxScale from GPL to the non-FOSS but source-available and time-limited Business source license (BSL) [51] which defaults back after three years to GPL. [52] [53] In 2017 followed version 1.1, revised with feedback also from Bruce Perens. [54] [55]

For a long time D back-end source code was available but under a non-open source conform license, [56] because it was partially developed at Symantec and couldn't be relicensed as open source. [57] On April 9, 2017, also the back-end part could be relicensed to the open-source Boost Software License. [58] [59] [60]

On July 27, 2017 Microsoft Research changed the license of space combat simulator Allegiance from the MSR shared source license, [61] under which the game was opened in 2004, [62] to the MIT license. [63] [64]

See also

Related Research Articles

<span class="mw-page-title-main">GNU Lesser General Public License</span> Free-software license

The GNU Lesser General Public License (LGPL) is a free-software license published by the Free Software Foundation (FSF). The license allows developers and companies to use and integrate a software component released under the LGPL into their own software without being required by the terms of a strong copyleft license to release the source code of their own components. However, any developer who modifies an LGPL-covered component is required to make their modified version available under the same LGPL license. For proprietary software, code under the LGPL is usually used in the form of a shared library, so that there is a clear separation between the proprietary and LGPL components. The LGPL is primarily used for software libraries, although it is also used by some stand-alone applications.

<span class="mw-page-title-main">Apache License</span> Free software license

The Apache License is a permissive free software license written by the Apache Software Foundation (ASF). It allows users to use the software for any purpose, to distribute it, to modify it, and to distribute modified versions of the software under the terms of the license, without concern for royalties. The ASF and its projects release their software products under the Apache License. The license is also used by many non-ASF projects.

The Netscape Public License (NPL) is a free software license, the license under which Netscape Communications Corporation originally released Mozilla.

<span class="mw-page-title-main">VLC media player</span> Free and open-source media-player and streaming-media-server

VLC media player is a free and open-source, portable, cross-platform media player software and streaming media server developed by the VideoLAN project. VLC is available for desktop operating systems and mobile platforms, such as Android, iOS and iPadOS. VLC is also available on digital distribution platforms such as Apple's App Store, Google Play, and Microsoft Store.

The Mozilla Public License (MPL) is a free and open-source weak copyleft license for most Mozilla Foundation software such as Firefox and Thunderbird. The MPL license is developed and maintained by Mozilla, which seeks to balance the concerns of both open-source and proprietary developers; it is distinguished from others as a middle ground between the permissive software BSD-style licenses and the General Public License. So under the terms of the MPL, it allows the integration of MPL-licensed code into proprietary codebases, but only on condition those components remain accessible.

<span class="mw-page-title-main">GnuTLS</span> Free software library implementing TLS

GnuTLS is a free software implementation of the TLS, SSL and DTLS protocols. It offers an application programming interface (API) for applications to enable secure communication over the network transport layer, as well as interfaces to access X.509, PKCS #12, OpenPGP and other structures.

The Common Development and Distribution License (CDDL) is a free and open-source software license, produced by Sun Microsystems, based on the Mozilla Public License (MPL). Files licensed under the CDDL can be combined with files licensed under other licenses, whether open source or proprietary. In 2005 the Open Source Initiative approved the license. The Free Software Foundation (FSF) considers it a free software license, but one which is incompatible with the GNU General Public License (GPL).

<span class="mw-page-title-main">Free and open-source software</span> Software whose source code is available and which is permissively licensed

Free and open-source software (FOSS) is a term used to refer to groups of software consisting of both free software and open-source software, where anyone is freely licensed to use, copy, study, and change the software in any way, and the source code is publicly available so that people are encouraged to improve the design of the software. This is in contrast to proprietary software, where the software is under restrictive copyright or licensing and the source code is hidden from the users.

A permissive software license, sometimes also called BSD-like or BSD-style license, is a free-software license which instead of copyleft protections, carries only minimal restrictions on how the software can be used, modified, and redistributed, usually including a warranty disclaimer. Examples include the GNU All-permissive License, MIT License, BSD licenses, Apple Public Source License and Apache license. As of 2016, the most popular free-software license is the permissive MIT license.

Alternative terms for free software, such as open source, FOSS, and FLOSS, have been a controversial issue among free and open-source software users from the late 1990s onwards. These terms share almost identical licence criteria and development practices.

Tivoization is the practice of designing hardware that incorporates software under the terms of a copyleft software license like the GNU General Public License, but uses hardware restrictions or digital rights management (DRM) to prevent users from running modified versions of the software on that hardware. Richard Stallman of the Free Software Foundation (FSF) coined the term in reference to TiVo's use of GNU GPL licensed software on the TiVo brand digital video recorders (DVR), which actively block modified software by design. Stallman believes this practice denies users some of the freedom that the GNU GPL was designed to protect. The FSF refers to tivoized hardware as "proprietary tyrants".

This comparison only covers software licenses which have a linked Wikipedia article for details and which are approved by at least one of the following expert groups: the Free Software Foundation, the Open Source Initiative, the Debian Project and the Fedora Project. For a list of licenses not specifically intended for software, see List of free-content licences.

<span class="mw-page-title-main">Public-domain-equivalent license</span> License that waives all copyright

Public-domain-equivalent license are licenses that grant public-domain-like rights and/or act as waivers. They are used to make copyrighted works usable by anyone without conditions, while avoiding the complexities of attribution or license compatibility that occur with other licenses.

The Affero General Public License is a free software license. The first version of the Affero General Public License (AGPLv1), was published by Affero, Inc. in March 2002, and based on the GNU General Public License, version 2 (GPLv2). The second version (AGPLv2) was published in November 2007, as a transitional license to allow an upgrade path from AGPLv1 to the GNU Affero General Public License.

License proliferation is the phenomenon of an abundance of already existing and the continued creation of new software licenses for software and software packages in the FOSS ecosystem. License proliferation affects the whole FOSS ecosystem negatively by the burden of increasingly complex license selection, license interaction, and license compatibility considerations.

License compatibility is a legal framework that allows for pieces of software with different software licenses to be distributed together. The need for such a framework arises because the different licenses can contain contradictory requirements, rendering it impossible to legally combine source code from separately-licensed software in order to create and publish a new program. Proprietary licenses are generally program-specific and incompatible; authors must negotiate to combine code. Copyleft licenses are commonly deliberately incompatible with proprietary licenses, in order to prevent copyleft software from being re-licensed under a proprietary license, turning it into proprietary software. Many copyleft licenses explicitly allow relicensing under some other copyleft licenses. Permissive licenses are compatible with everything, including proprietary licenses; there is thus no guarantee that all derived works will remain under a permissive license.

<span class="mw-page-title-main">Free-software license</span> License allowing software modification and redistribution

A free-software license is a notice that grants the recipient of a piece of software extensive rights to modify and redistribute that software. These actions are usually prohibited by copyright law, but the rights-holder of a piece of software can remove these restrictions by accompanying the software with a software license which grants the recipient these rights. Software using such a license is free software as conferred by the copyright holder. Free-software licenses are applied to software in source code and also binary object-code form, as the copyright law recognizes both forms.

BSD licenses are a family of permissive free software licenses, imposing minimal restrictions on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license was used for its namesake, the Berkeley Software Distribution (BSD), a Unix-like operating system. The original version has since been revised, and its descendants are referred to as modified BSD licenses.

<span class="mw-page-title-main">GNU General Public License</span> Series of free software licenses

The GNU General Public License is a series of widely used free software licenses or copyleft that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general use and was originally written by Richard Stallman, the founder of the Free Software Foundation (FSF), for the GNU Project. The license grants the recipients of a computer program the rights of the Free Software Definition. These GPL series are all copyleft licenses, which means that any derivative work must be distributed under the same or equivalent license terms. It is more restrictive than the Lesser General Public License and even further distinct from the more widely used permissive software licenses BSD, MIT, and Apache.

GNU LibreDWG is a software library programmed in C to manage DWG computer files, native proprietary format of computer-aided design software AutoCAD. It aims to be a free software replacement for the OpenDWG libraries. The project is managed by the Free Software Foundation (FSF).

References

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  2. O'Riordan, Ciaran (2006-11-10). "How GPLv3 tackles license proliferation". linuxdevices.com. Archived from the original on 2007-12-18.
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  5. Licensing HOWTO by Eric Steven Raymond&Catherine Olanich Raymond "Changing an existing license [...]You can change the license on a piece of code under any of the following conditions: If you are the sole copyright holder[...]If you are the sole registered copyright holder[...] If you obtain the consent of all other copyright holders[...]If no other copyright holder could be harmed by the change" (accessed on 2015-11-21)
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  8. On the Netscape Public License by Richard Stallman on GNU.org
  9. "Mozilla Relicensing FAQ Version 1.1". mozilla.org. Archived from the original on 2010-05-13. Some time ago mozilla.org announced its intent to seek relicensing of Mozilla code under a new licensing scheme that would address perceived incompatibilities of the Mozilla Public License (MPL) with the GNU General Public License (GPL) and GNU Lesser General Public License (LGPL).
  10. Relicensing Complete on gerv.net by Gervase Markham (March 31, 2006)
  11. February 2001 on xiph.org "With the Beta 4 release, the Ogg Vorbis libraries have moved to the BSD license. The change from LGPL to BSD was made to enable the use of Ogg Vorbis in all forms of software and hardware. Jack Moffitt says, "We are changing the license in response to feedback from many parties. It has become clear to us that adoption of Ogg Vorbis will be accelerated even further by the use of a less restrictive license that is friendlier toward proprietary software and hardware systems. We want everyone to be able to use Ogg Vorbis.""
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  13. Denis-Courmont, Rémi. "VLC media player to remain under GNU GPL version 2". videolan.org. Retrieved 2015-11-21. In 2001, VLC was released under the OSI-approved GNU General Public version 2, with the commonly-offered option to use "any later version" thereof (though there was not any such later version at the time). Following the release by the Free Software Foundation (FSF) of the new version 3 of its GNU General Public License (GPL) on the 29th of June 2007, contributors to the VLC media player, and other software projects hosted at videolan.org, debated the possibility of updating the licensing terms for future version of the VLC media player and other hosted projects, to version 3 of the GPL. [...] There is strong concern that these new additional requirements might not match the industrial and economic reality of our time, especially in the market of consumer electronics. It is our belief that changing our licensing terms to GPL version 3 would currently not be in the best interest of our community as a whole. Consequently, we plan to keep distributing future versions of VLC media player under the terms of the GPL version 2. [...]we will continue to distribute the VLC media player source code under GPL "version 2 or any later version" until further notice.
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  20. Version 2.99.4 (released 2011-07-23)[...] ** libgnutls: license upgraded to LGPLv3
  21. 2013-03-14 Nikos Mavrogiannopoulos (nmav@gnutls.org) * COPYING.LESSER, README: gnutls 3.1.10 is LGPLv2.1
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  25. Wikipedia + CC BY-SA = Free Culture Win! on creativecommons.org by Mike Linksvayer, June 22nd, 2009
  26. Licensing update rolled out in all Wikimedia wikis on wikimedia.org by Erik Moeller on June 30th, 2009 "Perhaps the most significant reason to choose CC-BY-SA as our primary content license was to be compatible with many of the other admirable endeavors out there to share and develop free knowledge"
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  29. OGRE Will Switch To The MIT License from 1.7 on ogre3d.org by sinbad (Sep 15, 2009)
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  37. "license". freecadweb.org. 2014. Retrieved 2015-03-25. Licences used in FreeCAD - FreeCAD uses two different licenses, one for the application itself, and one for the documentation: Lesser General Public Licence, version 2 or superior (LGPL2+) […] Open Publication Licence
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  40. Relicensing Dolphin: The long road to GPLv2+ Written by JMC47, MaJoR on May 25, 2015
  41. Possible LGPL relicensing #2033 on github.com "GPL-incompatible dependencies such as OpenSSL are a big issue for library users, even if the library user is ok with the GPL."
  42. The LGPL relicensing is "official" now, and git master now has a --enable-lgpl configure option. by wm4 on github.com
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  52. MySQL daddy Widenius: Open-source religion won't feed MariaDB on theregister.com (August 2016)
  53. A new release of the MaxScale database proxy -- essential to deploying MariaDB at scale -- features a proprietary license on InfoWorld by Simon Phipps (Aug 19, 2016)
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  55. releasing-bsl-11 on mariadb.com by Kaj Arnö (2017)
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  60. switch backend to Boost License #6680 from Walter Bright on github.com
  61. allegiancelicense.txt Archived 7 November 2014 at the Wayback Machine Microsoft Research Shared Source license agreement ("MSR-SSLA")
  62. Colayco, Bob (2004-02-06). "Microsoft pledges Allegiance to its fanbase". gamespot.com. Archived from the original on 10 December 2013. Retrieved 2011-07-22.
  63. Horvitz, Eric (2017-07-28). "Allegiance Relicense Letter" (PDF). Director, Microsoft Research. Retrieved 2017-07-28. Microsoft Corporation ("Microsoft") hereby relicenses the Microsoft Video Game Allegiance source code found at https://github.com/FreeAllegiance/Allegiance/tree/master/src ("Allegiance Source Code") from the current Microsoft Research Shared Source license Agreement (MSR-SSLA) to the MIT license.{{cite web}}: External link in |quote= (help)
  64. FREEING Allegiance, How it Happened (sort of) on freeallegiance.org (2017-07-28)