Can I relicense GPL software I make even if there are contributors?
<p>I am about to release an open-source library (it's a derivative, but the original is MIT licensed). I'm considering releasing under GPLv3, especially since my understanding is that as the copyright holder, I'd be free to distribute it under a different license at the same time or later.</p>
<p>My concern is: can I still do that if other people contribute? In particular I want to keep the ability to release it under the LGPL or BSD licenses, with contributions made by others. (I understand that I would not be able to undo the release of the same code under GPLv3.)</p>

<p>Only if you get permission from the contributers, either expressly as an ability to relicense their contribution or a copyright grant to you so they no longer own their contribution.</p>

open-source-software gpl