I'm the author of Fulguris which is in conflict with Styx. Both projects are MPL 2.0. Fulguris is a fork of the decade old Lightning and Styx is just a rebrand of Fulguris. See also that other open source question.

In the future to prevent such abusive rebrands to fail to properly credit Fulguris and its contributors I want to make sure they have a legal requirement to prominently display something like: "Powered by Fulguris", hopefully making sure users of rebrands are aware of where they are coming from and who is actually providing them with the good stuff.

I'm considering using CPAL as it seems it was designed for that purpose. I'm also considering modifying MPL 2.0 by adding a badgeware close much like CPAL is a modification of an earlier MPL version.

I probably won't bother with a full relicensing as I would need to try get in touch with all 67 contributors which could be taking a while. Instead I'm thinking both license could live side by side as long as it is well defined to which files they apply. Any new file would fall under that new CPAL like license and I think I should also be able to relicense all existing files for which I have sole copyright.

Does that seems right to you? Any tips and advice are most welcome.

  • 2
    If the fork has stripped away copyright and license notices in contravention of the MPL, what makes you think they would honor attribution notices as required by the CPAL? However, I don't think you can change the license for existing code since you're not the sole copyright holder and are bound by the MPL as well, including the provision that “You may not attempt to alter or restrict the recipients’ rights in the Source Code Form.”
    – amon
    Commented Oct 29, 2021 at 19:38
  • He may have stripped some copyright. The license is there though. But yeah he may not want to respect the public attribution and for such a clear license violation I could take actions.
    – Slion
    Commented Oct 29, 2021 at 20:26
  • I'm well aware I can not change the license for the files I'm not the sole copyright holder. However there are quite few files I created and are the sole copyright holder. So I'm assuming I can change the license on them and other new files to come. That's not intended to restrict the license that was thus far granted. It is just changing the license that will be granted henceforth. It just partial relicensing of the code base.
    – Slion
    Commented Oct 29, 2021 at 20:36

1 Answer 1


I strongly suggest that you do not alter or modify any license language to create your own, like you suggested above ("I'm also considering modifying MPL 2.0"). That should only be done by lawyers. And any proprietary license has negative impact on the re-use of your code by others.

CPAL is in a niche, not many are using it. You need to be very sure if you actually want to go that way.

Instead of the re-licensing path, which you have been considering, I suggest you add verbose license and attribution notices in EACH of the files in your project. These should actually survive any forking (see section 3.4 of MPL v2.0). That would be in addition to the license.md and notice files you are anyhow using.

  • Thanks, yes, I decided not to bother coming up with my own license. However the move to CPAL is happening github.com/Slion/Fulguris/issues/256 I find such a license makes a lot of sense in my case. Reddit did use that license too.
    – Slion
    Commented Nov 9, 2021 at 15:14

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.