Backdrop Licensing FAQ

Since Habr's readers are familiar with the Drupal fork called Backdrop, and the Backdrop project itself also has explanations regarding the licensing of the CMS itself and extensions to it, I think it would be useful to roll out the translation of questions and answers on licensing this CMS, since the same has already been done for Drupal itself .

If I create a module or theme, should I apply a GPL license to them?

Yes. Modules and themes for Backdrop are derived from Backdrop. If you distribute them, you must do so under the terms of the GPL license version 2 or later. However, you do not have to distribute them all. (see next question below)
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When you distribute your module or theme, the GPL applies to any piece that directly interacts with parts of the Backdrop that is licensed under the GPL. This does not apply to images you create and flash files. However, if you make a new image based on a Backdrop image that is distributed under the terms of the GPL, then that image must also be licensed under the GPL.

If I create a module or theme, should I share it with anyone?

Not. The GPL license requires that if you create a derivative work from Backdrop and distribute it to someone, you must provide the person with its source code under the terms of the GPL so that it can be modified and distributed also under the terms of the GPL. However, you are not required to distribute the code to anyone else. If the code is used only by you or within your organization, such use is not considered a distribution of the code, therefore the requirement to disclose the code in this case does not apply.

However, if your module is a general purpose, it is often a good idea to still provide the code to the community in a public repository. You can receive feedback, error messages and pull requests for new functionality from other people for whom your module will be useful.

Can I sell Backdrop or Backdrop module or Backdrop theme?

Yes. However, you must distribute it under the terms of the GPL license version 2 or later, so what you sell must also be available for modification and distribution (presumably for free). See the previous question.

Can I publish my work under the GPL version 3 license or only under the GPL version 2?

Yes. Since Backdrop users can choose which GPL license they want to use (version 2 or version 3), any module or theme created for Backdrop can be distributed under any of these licenses. However, if a module comes with one package along with Backdrop, all code included in such a package must be licensed under the same license. For this reason, the use of the same license “GPL version 2 or later” for any module or theme integrated into Backdrop is encouraged.

Will Backdrop license GPL version 3?

Since Backdrop is licensed under the terms of the GPL version 2 or later license, Backdrop may be distributed under the terms of the GPL version 3 license. This provides the flexibility for users to choose their version of the license. There are currently no plans to distribute Backdrops only under license version 3 or later.


Fragments of the text of this page were borrowed and modified from the Drupal licensing FAQ.