What to read about selling exceptions to the GNU GPL?

Question

Copyright

Actually, it is extremely scarcely possible to find something about dual licensing under the GNU GPL + commercial.
Does anyone have links to read about this topic?
Interested in general questions and application examples.
Courts on this topic (if they were anywhere at all) would probably be interesting too

Answer 1

> dual licensing under GPLv3 + commercial
GNU GPL + proprietary, presumably you mean. In general, this practice has a very clear name - selling exceptions to copyleft . It is imprudent to call this “dual licensing”, if only because there may well be (and most likely will be) much more than two different licenses: perhaps you will sell a fixed-term non-free license to someone, a perpetual license to someone, a limit on the number of cars, someone - without, and so on.
Also, this practice is not limited in any way by the current third version of the GNU GPL. And surprisingly, not limited even by the strong copyleft of the GNU GPL or the GNU Affero GPL; some comrades manage to sell exceptions to the weak GNU *Lesser* GPL copyleft; examples: Qt, CppCMS.
I really don’t even know what to read here - the practice is as simple as a stump. The only thing that needs to be taken care of is agreements with future free co-authors (contributor agreements), if they want to appear. Since you obviously have to be eligible to sell exceptions for your own pocket, which ideally (for you) means being the sole owner of the program, co-authors will have to be asked for a copyright assignment. A good example of such an agreement is traditionally considered ownCloud 's.
In addition to the three mentioned, there are more examples from different areas: MySQL (database), Ghostscript (library for PS and PDF support), ChibiOS (real-time OS).
In short, if you have specific questions, it's best to ask them.

Answer 2

https://habrahabr.ru/post/187540/
https://habrahabr.ru/post/284390/