Mozilla Public Licence (MPL 1.1)


To ensure that if Users distribute or release any modifications to the code, or new files into which your code has been copied, they must also make that source-code available on the terms of the MPL.

Key features

  • The spirit is that Users are free to use MPLed code in their applications and products (including proprietary products) provided that they make available any modifications they make to the actual MPLed code itself
  • New files that merely work with the licensed code need not be MPLed.

The MPL also provides that if you make a claim for a breach of your patent against a contributor or the initial developer of an MPL licensed material, then the licence granted to you terminates and you will no longer be entitled to use the MPL licensed material.

When should MPL licensed materials be used?

MPL licensed materials can restrict or limit you if you decide to use those materials in your work. You should check the conditions and requirements of the MPL to ensure that they can be complied with before using any MPL licensed materials. In particular, if you wish to release your source code under a different licence, then the use of MPL licensed materials in your work may not be suitable as the MPL requires you to release the source code to your software under the MPL and you are not allowed to impose any terms that limits or restricts the rights under the MPL.

When should materials be released under an MPL License?

The MPL is suitable for more complicated and complex software or materials that you have developed. It is usually suitable where flexibility is required on the initial developer’s part (ie you can release the software under multiple licence terms with the MPL) and where you would like modifications and developments made by other third parties to be contributed back to the source tree. However, as the MPL is quite complex, its suitability for your use will have to be assessed on a case by case basis to ensure that each party receives the benefit it requires (eg to meet industry requirement or fulfil commitments or contractual obligations that you or the University may have).