Jan Wildeboer jan.wildeboer@gmx.de wrote:
The way we understand the GNU General Public License all modules programmed to be used in our system must be published under the terms of the GPL. Our opinion is mainly based on this GPL-FAQ entry: http://www.fsf.org/licenses/gpl-faq.html#GPLAndPlugins
This is due to the fact that shipping/payment modules use objects generated by our project (the cart object, customer address etc.). So we are quite sure that the second part of this FAQ-entry is valid in this context, so all modules written for our project MUST be published under the terms of the GPL or a GPL-compatible license.
I believe this to be the case, but I'm unable to find any documentation on how plug-ins integrate with your software. (I am asked to give you my details before being allowed to read the FAQ!) Are they really linked in, or could they be counted as separate programs? Can someone more familiar with PHP confirm that this use of objects is similar to that in C++ or other more common languages, please?
Also, you ought to follow the instructions of how to apply the GPL to your software more closely. Most of your files seem not to have any copyright information, for example. Are they covered by the GPL or another "Open Source" licence? This may be part of the reason for the third party company's confusion.