Workshop: Legal aspects of free and open source software
exceptions or to distribute the software under various licences, called dual or
Re-distribution of the code of a project "ALPHA" covered by the EUPL is possible
inside another project (i.e. "BETA", possibly known as a "forking", with another
owner, brand name, logo, web site etc.), and it must be done under the same EUPL
Such forking, as described in the latter scenario, is rare, at least when the original licensor
organises an active community around its ALPHA project. If this is the case, all
improvements will be done on ALPHA without any code re-licensing.
By exception, forking may occur for 1) licensing / philosophical reasons or 2) for
A first example, is the case where the ALPHA licensor has lost its independence (i.e.
is purchased by a proprietary vendor), and the community decides to re-launch to
preserve EUPL licensing (not likely to happen if the licensor is a public sector
A second example is the case where the ALPHA licensor does not want to
integrate/support new functions. For example, the Indian government wants to
localise/adapt software distributed by the European Parliament in local Indian
languages, but the EP does not want to be involved in this process. However, the
new Indian project must also be distributed under the EUPL. The hypothesis where
a significant portion of the covered code is merged in another project is similar: as a
derivative, this project must be covered by the EUPL, in case it is distributed.
Once again, let’s underline the importance of an active supporting community: no forking
will be sustainable in the long term without such a support.
4.3. Exception to the “normal copyleft” The third paragraph of Article 5 of the EUPL reads as follows:
“If the Licensee Distributes and/or Communicates Derivative Works or copies thereof based upon both the Original Work and another work licensed under a Compatible Licence, this Distribution and/or Communication can be done under the terms of this Compatible Licence.” In the EUPL v1.2, a list of compatible licences is published in Appendix and contains the
GNU General Public License (GPL) v. 2, v. 3 -
GNU Affero General Public License (AGPL) v. 3 -
Open Software License (OSL) v. 2.1, v. 3.0 -
Eclipse Public License (EPL) v. 1.0 -
CeCILL v. 2.0, v. 2.1 -
Mozilla Public Licence (MPL) v. 2 -
GNU Lesser General Public Licence (LGPL) v. 2.1, v. 3 -
Creative Commons Attribution-ShareAlike v. 3.0 Unported (CC BY-SA 3.0) - for works
other than software -
European Union Public Licence (EUPL), any version as from 1.1 The interoperability exception will allow recipients to launch a new project DELTA, to reuse
files or source code covered by one of the above licences in the DELTA project, to insert or
merge the EUPL covered code in DELTA and to licence DELTA as a whole under this
Policy Department C: Citizens' Rights and Constitutional Affairs
Figure 3 Exception for compatible licences
Conditions for such « variable copyleft » are as follows:
Software code covered by the EUPL is combined in/with another, different work.
The combination (larger work) forms a derivative. Merged code must be licensed
globally as a whole. Keeping distinct licences (like for the various parts of an
aggregate) is not possible.
The other work, in which the code covered by the EUPL is merged, had been
obtained under a compatible licence (according to the list).
The same compatible licence (according to the list) is used to license the new
larger work “as a whole”.
The exception for compatible licence described above should not be understood as the
possibility to "relicense" a project
. As said above, this is obviously not the case: the reuse
of some code in the project "DELTA" will not impact the project "ALPHA".
Is there any risk to see someone licensing some trivial code (like “hello world”) under a
compatible licence for creating a “formal larger work” and licensing it under this compatible
licence? No cases were reported in five years EUPL distribution (2007-2012). It is not the
way FOSS operates. Making trivial forking is losing time and reputation. A forked work is
sustainable only when a working community takes it over and improves it substantially.
4.4. Exception to the exception Because three of the listed compatible licences are more moderately “copyleft” (or only at
file level) it may be that some code covered by the EUPL could also be reused in a third
generation project covered – in binary executable form - by a non-FOSS licence.
For example, the too brief formulation used by the Free Software Foundation may induce recipients in error :
« The EUPL allows relicensing to GPLv2, because that is listed as one of the alternative licenses that users may convert to »