Mark Jaquith 11:11 pm on January 14, 2011
Tags: GPL ( 2 )

Clarification in Licensing Language

WordPress has always stated that its license was the GNU GPLGPL GNU General Public License. Also see copyright license., and has bundled version 2 of the license, even though no GPL version was specified. The text of version 2 (as well as 1 and 3) says that if no version is specified, the software can be redistributed under the terms of any version of the GPL published by the FSF.

However, WordPress contains libraries which are licensed under the GPL “version 2 or any later version,” which obviously excludes version 1 of the GPL. Here is the reality: the GPL version 1 is effectively irrelevant. It hasn’t been a commonly used license since before Matt Mullenweg was in third grade! Clarifying WordPress as being licensed under the GPL “version 2 or later” resolves these niggling library licensing concerns or ambiguities, and clarifies where WordPress stands.

It was the intention of the WordPress founders and developers to be GPL version 2 or later from the beginning, and we have now made that license properly explicit.

#gpl

Lloyd Budd 11:53 pm on January 14, 2011

This is a good news! Not because of the version 1 irrelevant angle, but because hopefully pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party and theme developers will mimic this. Currently, most I see are explicitly only GPLGPL GNU General Public License. Also see copyright license. v2.
- Mark Jaquith 1:33 am on January 15, 2011
  
  Indeed. And on that topic, it might be good to change (going forward) the license-less assumption of WordPress.orgWordPress.org The community site where WordPress code is created and shared by the users. This is where you can download the source code for WordPress core, plugins and themes as well as the central location for community conversations and organization. https://wordpress.org/’s pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party directory to be “GPLGPL GNU General Public License. Also see copyright license. v2 or later” instead of “GPL v2.”
Alex M. 12:08 am on January 15, 2011

This is great news indeed. It now clarifies that I can use GPLGPL GNU General Public License. Also see copyright license. v3 code in a pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party without any issue.
- Mark Jaquith 1:31 am on January 15, 2011
  
  But you can’t host it in the WordPress pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party repository. And it couldn’t be pulled in to WordPress coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress.. I’d recommend that you license plugins as “GPLGPL GNU General Public License. Also see copyright license.” or “GPL version 2 or later” for maximum compatibility.
  - Alex M. 1:34 am on January 15, 2011
    
    All my personal code is licensed under WordPress’ license, but the issue is I want to make use of a package that is released specifically under GPLv3, specially Flowplayer. Seems I still can’t use it then (as no point if I can’t host it on WP.org).
    
    There’s no decent Flash video player out there that I can find that is GPLv2. 🙁
demetris 12:11 am on January 15, 2011

“It was the intention of the WordPress founders and developers to be GPLGPL GNU General Public License. Also see copyright license. version 2 or later from the beginning, and we have now made that license properly explicit.”

If WordPress itself was written in code as foggy and evasive as that statement, then WordPress would have never shipped because WordPress would have never worked. 🙂
- Mark Jaquith 1:27 am on January 15, 2011
  
  There is some evidence of that intention (or at least, ambiguity), which you can see in the public repositories of b2 and WordPress if you’d like. Alternatively, you could just trust us when we say that GPLv1 compatibility is not something we’ve ever cared about!
  
  We want the fogginess to go away: GPLv2+.
  - demetris 8:20 am on January 15, 2011
    
    Mark, the issue I see here is that what is presented as clarification is probably relicensing. (Depending on how one reads Section 9 of GPLv2.)
    
    Relicensing requires permission from everyone who has ever contributed to the code base. An intepretation of what the true intention of “the WordPress founders and developers” was is not enough.
  - Mark Jaquith 3:02 pm on January 15, 2011
    
    Switching to a non-GPLGPL GNU General Public License. Also see copyright license. license would require a relicensing effort. But merely choosing a subset of GPL versions to distribute WordPress under does not require such an effort, because the terms of the GPL (any version) allow us to distribute WordPress under any version (or range of versions) that we choose. You can’t say that the GPL “any version” grants the freedom for anyone else to distribute WordPress under a version of the GPL of their choosing, but does not grant that freedom to WordPress itself! There is a difference between “any version” and “all versions.”
    
    I’d be happy to discuss this in private, if you’d like further explanation. These sorts of discussions tend to get long-winded, and I don’t want to distract everyone with a big back-and-forth.
  - demetris 6:54 pm on January 15, 2011
    
    Thanks for the additional explanation! It makes better sense to me now.
    
    I’ve been supposing all along that Section 9 of the GPLv2 is open to conflicting interpretations, but when I look into it more carefully, it seems to me I didn’t have good grounds for supposing that.
    
    Cheers!
  - Denis 12:27 am on January 16, 2011
    
    IANAL, but wasn’t GPLGPL GNU General Public License. Also see copyright license. specifically bumped to v2 (among other things) to sort this out?
    - Mark Jaquith 12:32 am on January 16, 2011
      
      That was a mistake, that happened without discussion with the leads. It’s better to keep our options open with regards to GPLv3. For example, what if all the good third party libraries go GPLv3 or GPLv3+? We’d have to fork them and maintain them ourselves.
  - Denis 12:38 am on January 16, 2011
    
    That’s not the issue. The issue is whether you (as in WP) need to ask permission from everyone who has ever contributed to the code base… If so, I’ve yet to receive an email asking to accept (which, I’d answer yes to, of course; but from a technical standpoint, as I read the license, you’d need to do so, with, at your option, some statement along the lines of “if no reply by XYZ we’ll assume you accept”).
    - Mark Jaquith 5:15 am on January 16, 2011
      
      (@Dennis — I edited your comment to reflect the correction you sent in your followup comment).
      
      Think of it this way: GPLGPL GNU General Public License. Also see copyright license. “any version” means that anybody can distribute WordPress under any version of the GPL. Note my lack of quotes the second time. “any version” → “any version” isn’t required. It is “any version” → any version that we are doing.
      
      It’s strange, I know. But the GPL is sort of a strange copyright “hack.” But just look at all the literature from the FSF encouraging people to upgrade to GPLv3 or GPLv3+. They explicitly say that anyone (including the people running the project) has the option to upgrade from GPLv2+ or GPL “any version,” to a higher subset of GPL licenses. You do not need to ask permission from major contributors, because all three versions of the GPL say that if you don’t specify a version, it means “any version,” which means that anyone in possession of the code can release it under any version (or subset) allowed to them.
      
      What I’d like to make completely clear is that this is allowed by the GPL. Also, we couldn’t, for example, switch to another license like BSD or MIT without asking major copyright contributors for permission.
- Denis 6:13 pm on January 16, 2011
  
  Ya, I see how it could be interpreted that way as well.
  
  Regardless, I’d like to suggest that the WP foundation check with an IP lawyer and/or the FSF’s legal team if it hasn’t done so already, in order to be 100% sure. Clearing up license-related tickets (in which I’d include the Dolly-related one, which might also need the input of the RIAA) is, I think, urgently needed.
Chip Bennett 3:11 pm on January 15, 2011

Can you clarify this point?

Shouldn’t this wording be changed also, in light of the licensing clarification?

If WordPress is “GPLv2 (or at your option, any later version)”, then I can’t understand why a GPLv3 pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party would not be accepted into the repository.

Also: nice job on the license clarification. At least to my limited understanding, I think you’ve found the best solution.
- Chip Bennett 3:12 pm on January 15, 2011
  
  Hmm… comment-reply fail. This comment was in response to Mark Jaquith’s response to Alex M.
- Mark Jaquith 4:44 pm on January 15, 2011
  
  If we allow GPLv3 or GPLv3+ plugins into the repository, it makes it tricky to bring those into WordPress coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress. at some point.
  - hakre 4:45 pm on January 15, 2011
    
    Well, plug-in code pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party-code and coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress.-code is core-code, right?
    - Mark Jaquith 9:45 pm on January 15, 2011
      
      @hakre — Yes. But we should probably encourage maximum flexibility, which is granted by a GPLv2+-compatible license.
  - Chip Bennett 4:51 pm on January 15, 2011
    
    Okay, so they can’t be rolled into coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress.. I can buy that. (Not sure I totally agree with it, but that’s another conversation for another time.)
    
    But is the inability to roll a particular PluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party into core really a valid reason to prevent it from being available to WordPress end-users, through the repository? There’s a disconnect there that I’m just not understanding.
  - Travis 7:01 pm on January 23, 2011
    
    I’ll echo Chip’s question – why not allow a pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party into the repository, even if it can’t (currently) be rolled into coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress.? Sounds like Alex’s use case above (with flowplayer) is a perfect example of the end-users missing out on a potentially great plugin.
    
    I am asking out of complete ignorance, FYI.
Ryan Hellyer 10:55 pm on January 16, 2011

I had no idea it was possible to relicense between GPLGPL GNU General Public License. Also see copyright license. versions like that. I assumed once something was under one version, it was permanently stuck under that license until the license holder changed it. Good to hear things are locked in stone like that. Hopefully this will nip all those irritating license arguments that popped up not so long ago in TracTrac An open source project by Edgewall Software that serves as a bug tracker and project management tool for WordPress..
- hakre 3:03 pm on January 17, 2011
  
  I won’t call that actually re-licensing, wordpress.orgWordPress.org The community site where WordPress code is created and shared by the users. This is where you can download the source code for WordPress core, plugins and themes as well as the central location for community conversations and organization. https://wordpress.org/ as any other user has the right to choose the version of the GPLGPL GNU General Public License. Also see copyright license.-terms if the version has not been specified. That was written all the time in the license terms that shipped with wordpress. Naturally, the original terms still have to pass with the code otherwise this would violate the code’s GPL.’s terms.
  - Mark Jaquith 8:56 pm on January 17, 2011
    
    I wrote you an e-mail, so we can talk about “original terms” (like for b2, early WordPress) and the best way to convey that. If the e-mail address on this comment wasn’t the right address to use, provide me with a better one!
Denis de Bernardy 8:18 pm on January 17, 2011

I’m curious to know why there’s a long comment related to this that ended up in the trashTrash Trash in WordPress is like the Recycle Bin on your PC or Trash in your Macintosh computer. Users with the proper permission level (administrators and editors) have the ability to delete a post, page, and/or comments. When you delete the item, it is moved to the trash folder where it will remain for 30 days. without being published…
- Mark Jaquith 8:33 pm on January 17, 2011
  
  I replied to him privately, at length. I didn’t like the comment’s tone, and didn’t want to kick off a big long public debate over what may ultimately just be a lost-in-translationtranslation The process (or result) of changing text, words, and display formatting to support another language. Also see localization, internationalization. situation. Figured we could go back and forth in private a bit to get misunderstandings cleared up.
Mike Schinkel 6:58 pm on March 19, 2011

Question: Will a pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party be denied entry into the WordPress plugin repository if it depends on code that is ApacheApache Apache is the most widely used web server software. Developed and maintained by Apache Software Foundation. Apache is an Open Source software available for free. 2.0 licensed? Specifically flot includes excanvas. For reference:

http://lists.automattic.com/pipermail/wp-hackers/2011-March/038334.html
- scribu 10:37 pm on March 19, 2011
  
  https://core.trac.wordpress.org/ticket/16898

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Clarification in Licensing Language

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