New version of the MPL open source license released

Open source software development is booming nowadays, and one of the unfortunate legal challenges related to this trend stems from the large variety of open source licenses being used in practice. Generally, these licences grant the license holders certain rights that are less prevalent in traditional licenses, such as the right to obtain a copy of the source code, the right to make derivative works of the software, and the right to distribute both the original and modified versions.

Despite these common similarities, there are some important differences between these licenses, which can often make it difficult to re-use multiple open source software packages to create a new programme. For instance, imagine that you want to create new software by combining two existing open source packages and adding your own code on top. The first package is distributed under the General Public License (GPL), and requires you to distribute your own programme under the GPL as well. The second package however only allows its re-use with a clause prohibiting any commercial use. Is it possible to combine those programmes into new software without violating the terms of one (or both) of these licenses? This type of question is referred to as a license compatibility issue, and is one of the more common open source questions IT lawyers need to deal with.

The well known Mozilla Public License (MPL, used for instance by Mozilla Firefox and Thunderbird) faced a similar challenge: the existing v1.1 was felt to be incompatible with two very common open source licenses, namely GPL and Apache. This was a problem, as it was impossible to create software containing both MPL code and code under one of these other licenses.

However, version 2.0 of the MPL has just been publicly released, and has been modified to permit this combination. This is possible because the MPL is a 'file level'-license, meaning that only modifications to MPL-code themselves need to be licensed under the terms of the MPL, whereas the software as a whole (a 'Larger Work', in the terms of the MPL) can be licensed under another license, such as e.g. the GPL, or even a proprietary license. This should hopefully make it easier to use MPL code in a wider variety of software projects.

For any questions on this topic, please contact Hans Graux.