License compatibility
License compatibility refers to the problem with licenses of software packages which can contain contradictory requirements, rendering it impossible to combine source code from such packages in order to create new software packages.[1]
For example, suppose one license says "modified versions must mention the developers in any advertising materials", and another license says "modified versions cannot contain additional attribution requirements". If someone combined a software package which uses one license with a software package which uses the other, it would be impossible to legally distribute the combination because the two requirements cannot be simultaneously fulfilled. Thus, these two packages would be license-incompatible.[2]
Not all licenses approved by OSI or by the Free Software Foundation are compatible with each other, thus not all the code under OSI or FSF approved licenses can be mixed. For example new software which mixes code released under the Mozilla Public License with code under the GNU General Public License (both licenses are OSI and FSF approved) cannot be distributed in a way which does not violate the terms of the GPL or the MPL. The FLOSS License Slide shows if some common licenses are compatible.
GPL compatibility
Many of the most common free software licenses, such as the original MIT/X license, BSD licenses (in the current 2-clause form), and the LGPL, are "GPL-compatible". That is, their code can be combined with a program under the GPL without conflict (the new combination would have the GPL applied to the whole). However, some free/open source software licenses are not GPL-compatible.
Also see the list of FSF approved software licenses for examples of compatible and incompatible licenses.
See also
References
- ^ "How GPLv3 tackles license proliferation". Archived from the original on 2007-12-18.
- ^ "Stallman explains license compatibility while discussing GPLv3".
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