I have an Android Game I've written that I released under the MIT license. Recently, there have been several people who have downloaded the source of my application, added ads and uploaded it to the Google Play store.

While this irks me, there's nothing legally wrong with what they are doing since my project is licensed under the MIT license. In order to stop this however, I'd like to relicense my application under the GPL.

The entirety of the code in its current state was written by me (minus ~3 lines or so that can be easily removed), however, the app has been translated into a few different languages by users, who have added their translations through GitHub pull requests.

Two Questions:

  1. Is relicensing my project under the GPL an good way to stop people from reuploading it as proprietary software with ads?

  2. If I decide to relicense my project under the GPL, do I need to track down everybody who has modified the translation files and get their permission? I know that this is the case when it comes to the code, however I'm not sure how this works with non code assets.

  • 1
    This doesn't answer the question but is important to understand your rights. Check if the apps include your copyright notice and the MIT license. If not, they are in violation of the license and you can sue them for copyright infringement and damages. I'm not a lawyer but as far as I can see the damages would be not attributing your work because if your work was rightfully attributed you would be getting publicity from the app's users. Commented Aug 13, 2022 at 2:33

1 Answer 1


Just like everyone can take your MIT-licensed software and make it proprietary without having to ask all of its authors for permission, you can take your MIT-licensed software and license it under the GPL without asking the contributors.

MIT-licensed software can be integrated/made into GPL-licensed software. The other way around is not possible.

The FSF curates a list of GPL-compatible licenses, which includes the two licenses often called "MIT license":

  • X11 license

    […] is a lax permissive non-copyleft free software license, compatible with the GNU GPL

  • Expat license

    […] is a lax, permissive non-copyleft free software license, compatible with the GNU GPL

If you change the license to the GPL, and make changes to the software so that it differs from the version that is (and always will be) licensed under MIT, no one may distribute this new version as proprietary software without asking all authors for permission.

Of course this doesn’t stop someone from including ads in the software, but they would have to follow the terms of the GPL when distributing it (i.e., providing the source code and licensing it under the GPL, too).

  • 1
    To expand on the other half of this question, in almost every case I have seen, translation files are considered part of the source for a given program. (If source is speech, speech can also be source). So in the example, you have given, you would likely also need to either get explicit permission to re-license the translation files or remove them from the project. (IANAL/IANYL)
    – xzilla
    Commented Aug 6, 2019 at 2:03
  • 2
    @xzilla read the answer more carefully. MIT-licensed content can be used as part of a project which is licensed in its entirety under the GPL. The translation files can be reused in this way, and are therefore not an issue.
    – MadHatter
    Commented Nov 13, 2019 at 8:57
  • 2
    @Martian2020 yes, I meant the licence governing the new work will be the GPL, as the GPL requires, and this is permitted because the MIT licence requires that its text be reproduced, but not that it also be the sole applicable copyright licence. If that's still unclear, I recommend asking a new question, instead of continuing the discussion here.
    – MadHatter
    Commented Sep 10, 2021 at 7:17
  • 1
    @Martian2020 it doesn't. A work is a thing, entire of itself; if the new work is the combination of the old MIT-licensed work and anything under GPL that's been added, this entire work must be distributed under GPL. I have said that three times now, for all that you seem very keen to have me clarify that I've not said it at all.
    – MadHatter
    Commented Sep 11, 2021 at 6:13
  • 2
    @Martian2020 then I encourage you to read this answer on law.SE. I also recommend the approach I take in this answer: once code received under MIT is placed under the GPL tarpaulin - which MIT allows - it may not be taken out again (without much consent). You can get it from the original distributor, under the original licence, but you may not abstract it from the GPL'ed work and claim it is again under MIT-only.
    – MadHatter
    Commented Sep 11, 2021 at 16:36

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.