GPLv2 license question with "derived work"

I work for a Germany based software company specialized in eCommerce solutions. In the near future we intend to build a system based on nopCommerce (either as a whole derivation or as extensions/plugins while keeping the core intact... don't know yet in this early stage). Why? Because we don't want to reinvent the wheel anymore and nopCommerce is a fantastic piece of software with well-structured code and tons of features.

We plan to redesign the admin section incorporating the Kendo UI components, build a theming engine with several ready-to-use, configurable themes (config for colors, typo, banner, logo, placements etc.). Further we have to implement some payment plugins specific to the german market and meet some juristical requirements specific for germany, which are not given in nopCommerce at this moment (e.g. the so-called PAnGV, Trusted-Shops Certificate etc.). Some of this work we would provide as contributions to the nopCommerce core, if there is general interested of course.

Of course we want to monetarize our work, and here things get complicated: We sell proprietary software since 15 years now, so open-source is a rather new concept for us. Threfefore I apologize in advance if my concern sounds 'newbie' to you. From what I understood so far, GPLv2 permits commercial distribution of derived work, as long the derived work is also under the same license. But this actually means, our customer could give away the program and our modified source to anyone for free. Am I correct or did I miss something here?!

I stumbled upon a system called 'shopXpert' which actually gets sold. How does they handle the licensing issue? Do they reveal their sources?

I'm sorry, but I relly read TONS of docs and discussions about GPLv2, but I really am confused about the fine details of monetarizing (besides most infos are contrary). So I'm kindly asking ;-) Could you please enlighten me if our plans comply with your license requirements so we can start digging into nop...

Thanks in advance

vaybabo wrote:
You are allowed to sell copies of the modified program commercially, but only under the terms of the NPL (based on GNU GPL). Thus, for instance, you must make the source code available to the users of the program as described in the GPL, and they must be allowed to redistribute and modify it as described in the GPL (http://www.gnu.org/licenses/gpl-faq.html#GPLCommercially).

Also have a look at this post

And of course do not forget about the copyright removal key. Please see our license here ("Additional nopCommerce terms")

Andrei, thanks for your reply, but I have a follow-up question.

If we develop a project based on nopCommerce that is customer-specific, by local law, we are anyway obligated to release the code to that customer.

My question is: if we develop for example a cloud SaaS offering where customers can go and register and create their own stores, and pay subscription fees, does the code have to be made available to those customers?

Thanks for your help.

See this article

And what about Plugin, if we want to sell it commercially but under a different commercial license without source code? Does the GPL license allows this?

jariwalakrunal wrote:
You can sell it, but not under a different commercial license. See my first reply above and this FAQ