I used to contribute to a free iOS app on GitHub that was released under the Mozilla Public License Version 2.0.

Multiple people have since taken the code from that GitHub repository and released apps onto the app store based on that original code. Some of them have just released the app as is with only the name changed. Some have made extensive changes. None of them, that I'm aware of, have released the source to their changes.

Is there any recourse to get them to release their changes?

Has anyone had any success getting Apple to remove apps from their store, from developers who similarly ignore the terms of the original code's license?

2 Answers 2


It certainly sucks when people take your work and use it in ways against your permission, like copying your copyleft work without also sharing their changes. Fortunately you don't have to go straight to the lawyers, as there are a number of things you can do, and also some things to check, to be safe.

  1. Is it worth it? Copyright infringement for software is everywhere. Good projects attract lots of clones. But are these clones actually hurting you? Are they receiving significant numbers of downloads and market share compared to your own? Are they damaging your brand? Do some of the clones have useful enhancements, such that there is value in bringing their source into the free software ecosystem? If the answers are "no", then working and improving your project will be a better use of energy than pursuing these clones.

  2. Did they actually copy your code? In your case it seems like at least some are blatant copies, but it's better to be safe especially before taking drastic measures like accusing people of copyright infringement. Are their clones so similar, bugs and all, that it's blatantly obvious? Did you decompile the app and find significant similarities to your own? Remember that, as far as copyright is concerned, it's perfectly fine to copy ideas and functionality and write your own implementation.

  3. Did they actually violate the license? Most copyleft licenses only require you to give the source, or even just an offer of it, to recipients only, not the general public. Here's the actual text from the MPL:

    3.2. Distribution of Executable Form

    If You distribute Covered Software in Executable Form then:

    (a) such Covered Software must also be made available in Source Code Form, as described in Section 3.1, and You must inform recipients of the Executable Form how they can obtain a copy of such Source Code Form by reasonable means in a timely manner, at a charge no more than the cost of distribution to the recipient; and

    (b) You may distribute such Executable Form under the terms of this License, or sublicense it under different terms, provided that the license for the Executable Form does not attempt to limit or alter the recipients' rights in the Source Code Form under this License.

    So depending on the specifics, some of the clones may not be violating the MPL. They could mention the MPL and provide a source code download link in:

    • The app store page description
    • In a legal text dialog during the installation process
    • Somewhere inside an "about" section in the app itself

    My point is, there are many ways they can fulfil clause 3.2 (a) without it being obvious to people who have not downloaded and used the app.

  4. Write to them. Let them know that they are violating the MPL, and tell them how they can rectify this, or (if you have rights to do so), offer alternative licensing terms. Licenses, even open source ones, aren't trivial to follow - that's why there are services like tldrlegal, and this site. Try to keep a level head and assume good intentions; it's very likely that they simply aren't aware of the license violation, for example by assuming (as many people do) that "if it's free online I can do whatever I want with it".

  5. Write to the App Store. Go through their standard support channels for dealing with stuff like this. The cloner may not care about legalities but companies like Apple sure do, and are going to be on your side if you have a legitimate claim.

  6. Submit a DMCA takedown notice. By this point things will have become serious (and expensive) for you, as you should have consulted a lawyer on the matter, because there are legal consequences for filing incorrect DMCA takedowns. It's very likely that Apple will have a fast-track process for DMCA takedowns, due to having to deal with them constantly.

  7. Send a Cease and Desist letter. Ideally you will get a lawyer to do this, so that the letter is sufficiently intimidating.

  8. When all else fails, sue them.

  • 4
    This is a great answer. I would love to see this Q&A become canonical for other questions of the form, "Someone is distributing my program in violation of the license; what should I do?"
    – apsillers
    Commented Feb 11, 2016 at 18:39

In the described situation, you are copyright holder (at least in part), unless you assigned the rights to your contributions to some other entity. So you are in position to take legal action. You will have to check if the stipulations of the license were followed, in MPL's case that any changes to MPLed files are public if I'm not mistaken. They might very well be acting inside the rights the license grants.

It won't come cheap, and the most probable outcome is for you to go broke. Talk to your very own lawyer.

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