I recently purchased a WP plugin. This plugin has a free version on this site in the plugin repository and is licensed under GPL 2.
The plugin is great. It's robust, works nicely and is doing just what I need it to do. I'm happy to have paid for it and and I'm happy to keep paying for it to support the developer. However, having just received a upgrade, it's occurred to me that the developer appears to be violating the GPL license.
In the upgrade email I just received it says:
Please, note that this plugin licence is per 1 site.
You should not edit and/or (re)distribute this package.
When purchasing the plugin from the developer's site one is also faced with a choice between a 1 site license and a multi-site license.
My understanding is that this is all a violation of the GPL. You can't impose these restrictions on editing or distribution. Am I correct? If so I guess my next step should be to inform the developer?