I read several related questions about the use of GPLv3 in a commercial app but they don't say anything about a freemium app. I would like to use a GPLv3 library in two apps, a free one (with limited features) and a paid one.
Basically, the free app will allow to use the library without limitations, and the paid one will include it as well as other unrelated features.
I will release the free app under GPLv3 but do I need to release the paid one under the same license?
I don't want to release the whole source code of my paid app (for obvious reasons), as the other features don't use the library in any way. It would just be more convenient for users who bought the full version to have all features in a single app instead of putting the library in a separate one.