Licenses applied to software as copyrightable works, in source code as binary form,[1] can contain contradictory clauses.
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.
[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.
[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.
[14][15] In July 2013 the VLC application could then be resubmitted to the iOS App Store relicensed under the Mozilla Public License.
[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.
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".
[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.