@williampatton already published a post regarding the possible issues on theme licensing. Along with that, we can see lots of these shops are not declaring they are licensing properly on their website.
If your premium products are non-GPL GPL is an acronym for GNU Public License. It is the standard license WordPress uses for Open Source licensing https://wordpress.org/about/license/. The GPL is a ‘copyleft’ license https://www.gnu.org/licenses/copyleft.en.html. This means that derivative work can only be distributed under the same license terms. This is in distinction to permissive free software licenses, of which the BSD license and the MIT License are widely used examples. or not GPL compatible, you are not allowed to host your free theme in the WordPress repository. Knowingly or unknowingly, authors are missing this.
While visiting a couple of theme shop websites, I found some minor issues about the license:
- There is nothing mentioned about theme license. (No Terms and Condition)
- Some website mentioned, All Free and Premium Themes are under GPL License. (Nothing More)
- Some website has very detailed Terms that mention the license, but in their pricing, we can see limitations that are against the GPL. For example, One Site License or Install on One Site. As per the GPL license, you are not allowed to restrict usage or copying, including an installation limit.
- Some websites mentioned everything in a good way that is easy for customers to understand, and they have a totally well managed GPL license. For instance, Unlimited Site License, Support, and Updates are Available for One Year. This support the GPL compatible.
In which category The 'category' taxonomy lets you group posts / content together that share a common bond. Categories are pre-defined and broad ranging. does your website belong?
Update your website license if you want to host or continue hosting your themes on WP.org. Otherwise, all your theme will be suspended in the repository.
Free feel to comment below if you have different ideas or thoughts about the GPL License.