Change project licence?

[Michael Torrie]

On 09/14/2017 11:22 AM, Kryptxy via Python-list wrote:
> Hi,
> I have an opensource (python) project under GPL3 licence. I wish
> switch to MIT licence so as to make it more permissive. I know how to
> change the licence, but I want to know is it fine and wise to change
> the licence at this point? (The project already has 19 clones, 250+
> GitHub stars. Here: https://github.com/kryptxy/torrench)

If you are the sole copyright holder on the project, and haven't taken
in any contributions from anyone else, then you can change the license
however you like, regardless of clones/forks, with the caveat below.

If you've integrated pull's from other people, then they now own a piece
of the copyright and you would have to talk to each person and get
permission to relicense their code contribution.  Note that clone of
your repo does not constitute a contribution. I'm talking about a pull
request or patch that was contributed to your mainline repo.

Finally, even if you are the sole copyright holder, while you can change
the license on your code at any time to any terms, you cannot change the
license on code that has already been forked under your original GPLv3
license. In other words, if someone clones your project before the
license change, they can continue under original license, as per its
terms.  You can't retroactively change the license on code that's
already been distributed, at least under the terms of the GPLv3. (I'm
sure there's some license somewhere that expressly states the terms can
be retroactively modified. But not the GPLv3.)