Some time ago, I wrote a small program to automate a simple task. At the time, I released the program under the GPL license. I'm the sole author of the work and it was not created for hire (I was not under employment contract while making it or being paid for it).

Now I've been contacted by someone who has reused and incorporated the work, who at the time did not notice it was licensed under GPL. I've been asked if I'd be willing to release the work under another license so they can keep using my work as part of a closed source commercial project. (Something they wrote at work).

I'm not against this, but am I even allowed to do that? Am I free to rescind the share-alike requirement of GPL by just issuing the same work under another, more permissible license?

Can I say "I release this to you under $license additionally?" I was thinking cc0 to completely wash my hands of it, but is that even possible? I don't want to expose myself to any liability doing this.

2 Answers 2


Yes, you can license the work under new terms to everyone or just to this one person, as you like.

You don't need to release a new version to add a license. If you did, then companies that sell licenses to use their software would have to bump the version number every time somebody bought one.

Am I free to rescind the share-alike requirement of GPL by just issuing the same work under another, more permissible license?

You aren't rescinding anything. The person you're granting the new license to never accepted the terms of the GPL. The GPL has no power over them. The only reason anyone chooses to follow the requirements of the GPL is that it grants them some rights if they do. Using the software doesn't automatically make them subject to the GPL, it just makes them guilty of copyright infringement if they don't abide by the GPL and their use isn't covered by some other license or by fair use, etc.

This person did infringe on your copyright. As the sole copyright owner you can handle that by simply choosing not to sue them. If you want to bind yourself legally to never suing them, then... why are you being so nice? It's their fault they infringed, if I were you I'd ask for some money. But if you want to tie your own hands for whatever reason, then I'm not sure how you'd do it. You should ask at the Law SE, or see if there's an existing question there that covers it. A new license can prevent future infringement, but I don't think you can make it retroactive such that the earlier infringement never happened. I may be wrong.

  • 2
    You can retroactively grant a license for the use that was infringing under the original licence. The it becomes as if the infringement never happened. Oct 20, 2021 at 6:12
  • I ended up kicking the ball back to them since I did not want to spend further time researching how to absolve them of their mess up. So they ended up having me sign a contract that says I give them a license for the software and will not sue for copyright infringement for past use, for 50€. Apparently the payment is necessary to make the promise I'm signing legally enforceable, although the amount is arbitrary (I did not ask for payment).
    – Magisch
    Oct 20, 2021 at 12:40
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    I've seen examples of GPL software being explicitly licensed for use in closed proprietary software by the copyright holder on a case by case basis. Key is that only the original copyright holder of the release can approve this inclusion; I don't think you can fork a GPL project and then license your fork as a proprietary work, otherwise that would be a convenient workaround for anyone seeking to use GPL code in proprietary software.
    – fdmillion
    May 4, 2022 at 18:35

In general, as you are the sole author, you can release your work under any license and you can change the license at your will.

Since you cannot change the licence retroactively, you cannot say "Version x.y.z which was under GPL from today is under your-needed-license".

So I think that the the simplest solution is for you to relase a x.y.z+1 version under another license (or a dual lincese if you wish) and as long as they use that new version, they are in the clear legally even in the future or against some third part that can challenge them about licensing issue. (being a closed source commercial product, you can not care if they use it, but some of their competitor can try to provoke some legal issues to them, even if I don't see how)

  • Is there any way for me to future proof this in a way that makes it abundantly clear they will have no legal issues because they violated the license I released those years ago?
    – Magisch
    Oct 19, 2021 at 9:49
  • @magisch as I said, you cannot change retroactively a license. If the code they are using is under GPL, it will be under GPL forever. The only way is to release a new version under a new and more permissive license and tell them to use it. You don't even need to change the code itself. Oct 19, 2021 at 10:03
  • @magisch i guess write a contract saying you won't and both of you sign it? IDK, I am not a lawyer Oct 19, 2021 at 12:34
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    You can say to someone: For you, version x.y.z is also available under license X in addition to the GPL. You choose which terms you want to follow. That kind of license charge can also be applied to already released versions. Oct 19, 2021 at 14:58

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