After receiving some threats of the copyrights holder of a dual licensed software(GPL2 and commercial) to buy the commercial version for projects in production, I am thinking to make a fork.

In a case of GPL2 and commercially dual licensed with business owned copyrights software, is forking the GPL2 version an option?

Also, is forking a good way to deal with such cases?

Background information

The software is a web CMS released under 2 versions a GPL2 free open source edition and a commercial edition including technical support and extra functionality.

The problem is that now, basing their argumentation on the "distribution" definition of the GPL2, the company holding the copyrights argue that delivering the software and some extensions to a client is considered as a "distribution". And that such a "distribution" falls under the GPL2 obligation to release the custom made extension code.

Custom made extensions are mainly designs, templates and very specific functionality.

Basically they give me 3 choices:

  1. Buying the commercial licensed edition for projects based on the GPL in production,
  2. Deleting all the projects in production based on GPL2 version,
  3. Releasing all the extensions as GPL2 code.

The first 2 options are nothing realistic for finished projects.

The third option could be fine, but as most of the extensions are very specific, cleaning the code to make it usable by other users means lot of works and also I am not sure the clients will appreciate to have their website designs and specific functionality released publicly.

The copyrights holding company even contacted some clients directly, giving them the "choice".

I know that this is a very corporate interpretation of GPL2, and a such action is nothing close to legal, but as an independent developer, I don't want to take the risk to get involved in some long and tiring legal procedures.

PS. This question was first asked on Stack Overflow where it felt out of the scope and closed, after reading the present site FAQ, discussing about software licensing seems fine.

  • 2
    To satisfy GPLv2 you need to make the code available to your client, and license it under the GPLv2 or compatible. That doesn't mean you have to clean it up, or make it available to anyone else. So your solution might be as easy as including your extensions in a zipfile when you distribute the the client. Nothing stops the client from making this public, but nothing forces you too, either.
    – simon
    Oct 6, 2012 at 19:06

1 Answer 1


Usual disclaimer: Ask a lawyer etc.

By the GPL, you don't have to release source of your specific extensions to the public. All you have to do is to make it available to your customers, licensed under the GPL or a compatible license. Of course that means that your customers could decide to release it to the public, or do whatever else the GPL allows them, but they don't have to, either. Cleaning the code is not required by the GPL, and making is usable by other users is probably not even in your interest.

  • 3
    +1 GPL requires you to distribute the source to person X whenever you distribute the software to person X. Publishing source to whole world is not required, but does of course satisfy requirement to make source available to X. Worth mentioning that you must also require person X to abide by GPL, so your customers are in same position as you. Customers are free to extend the software &/or distribute it to others but they must make the source available to them and must require them to abide by GPL.
    – MarkJ
    Oct 6, 2012 at 9:27
  • Markj: Exactly. Whoever gets the binaries must be able to get the source and und use it.
    – user281377
    Oct 6, 2012 at 12:16

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