Using MIT Licensed niftyPlayer in a WordPress Hosted Plugin (Premium and Free versions)

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Apologies in advance if I meander in this question, I am trying to grasp my brain around the different licensing models and yes, I know most of you are not lawyers.

I am developing a WordPress Plugin that I intend on publishing a free version to the WordPress Plugin Directory and a premium version sold elsewhere. My plugin incorporates the Adobe Flash-based niftyPlayer (http://www.varal.org/niftyplayer/) which is licensed under the MIT License. The varal.org site states:

This program is licensed under the MIT License, which, to put it in non-legal terms, allows you to share, use and modify it. Even for commercial purposes. Check out the Wikipedia article on this license for more.

Since a WordPress Plugin by its own nature is a derived work from GPL-licensed WordPress it needs to be licensed under GPL and I believe that the GPL requires that any work
containing GPL-licensed software must be relicensed in its entirety under the terms of the GPL. With the plugin I am writing the player itself does not make any direct interactions with the WordPress core, it is just used on top of the site. Would the need to relicense apply to using the niftyPlayer in the plugin? Since the MIT license is pretty un-restricted, can I, and if so, how do I go about re-licensing it?

I have some follow-up questions but they essentially pertain to the need to re-license/not..

Thanks for any insight.

2 Answers
2

The GPL requires that any derived works are also licensed under the GPL. For the purpose of WordPress plugins and themes, that means any elements which rely on WordPress (ie, use or extend WordPress classes and functions) must also be GPL. You are allowed to license other elements not reliant on WordPress (eg CSS, images) under different terms. Since you’re talking about including external code in your plugin, the external code (ie niftyPlayer) does not have to be GPL, as while your plugin may rely on niftyPlayer to work, niftyPlayer does not rely on WordPress to work.

It’s also worth noting that the MIT License is compatible with the GPL, so it should be possible to produce a GPL-licensed plugin using MIT-licensed components.

we will only promote and host things on WordPress.org that are 100%
GPL or compatible.
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