Licensing LGPL software commercially

Question

We have a mobile app software and we distribute it with LGPL v3. It uses other 2 components licensed under LGPL-v3 and MIT. For our own code, we are have the full ownership (i.e. nobody else have made any contribution)

Later we created a modified version and customized it for a company and it will be distributing their own version of this mobile App. But this company doesn't want to publish the sources. How do we give the rights to this company to distribute the App without sources ? We did not modify the other components that our App uses, only our own code.

A simple mail saying "Hey, it is ok , you can distribute the binaries of our app without any problem, you have our permission" doesn't look very formal. So, how is this done legally?

What documents do we have to provide or what changes do we have to make in order to do this correctly?

Answer 1

A simple mail to the other company is indeed not sufficient to let them get out of the obligations that the LGPL license imposes on them. The only option to not have to obey those obligations is to receive the code under a different license.

As the sole copyright holders of the app, you have the option to offer the app to different people under different licenses. This means that you can offer the standard app under the LGPL license to the general public and modified versions under a closed-source license to companies that are willing to pay for that.

There is one snag in this scheme, and that is the LGPL-v3 library that you are using. As you don't own the copyrights of that library, you either need to check if the owners of that library also offer a dual-licensing scheme, or you need to obey the LGPL license terms with regard to that library. This means that you must make it possible for end-users to replace the LGPL library you use with a version of their own. This requirement must also be fulfilled if you distribute your app under a closed-source license, but does not imply that your sources must be available.

To dual-license your app, you need to ask your legal counsel to draft a contract and to put the desired license terms in it.