Relicensing an MIT licensed project under the GPL that has non code contributions from others? Legal action or illegal action?

Just like everyone can take your MIT-licensed software and make it proprietary without having to ask all of its authors for permission, you can take your MIT-licensed software and license it under the GPL without asking the contributors.

MIT-licensed software can be integrated/made into GPL-licensed software. The other way around is not possible.

The FSF curates a list of GPL-compatible licenses, which includes the two licenses often called "MIT license":

1. X11 license

[…] is a lax permissive non-copyleft free software license, compatible with the GNU GPL

2. Expat license

[…] is a lax, permissive non-copyleft free software license, compatible with the GNU GPL

If you change the license to the GPL, and make changes to the software so that it differs from the version that is (and always will be) licensed under MIT, no one may distribute this new version as proprietary software without asking all authors for permission.

Of course this doesn’t stop someone from including ads in the software, but they would have to follow the terms of the GPL when distributing it (i.e., providing the source code and licensing it under the GPL, too). #dev

Source: https://opensource.stackexchange.com/a/5833

Open Source Stack Exchange

Relicensing an MIT licensed project under the GPL that has non code contributions from others

I have an Android Game I've written that I released under the MIT license. Recently, there have been several people who have downloaded the source of my application, added ads and uploaded it to the