Question:
Good day, gentlemen!
I have a fork of a project whose code is released under GPLv3. I release the modules written by me under MPL1.1. Do I have the right to change the license for other modules from GPL to MPL if I made a significant part of the changes in them (naturally referring to the first author)?
Answer:
The copyright holder, in this case, the author has the right to change the licensing terms for new releases. However, since we are talking about a derivative work, all authors, regardless of contribution, are the copyright holder, therefore general agreement is necessary.
In any case, you cannot change the licensing rules for releases already under the GPL, they still require source code to be provided, and therefore anyone can fork.