For what it's worth, the MIT, X11, Apache 2, and (modified) BSD licenses all have the same feature of GPL compatibility, as does CC0 or any public domain dedica

For what it's worth, the MIT, X11, Apache 2, and (modified) BSD licenses all have the same feature of GPL compatibility, as does CC0 or any public domain dedication. (MPL 2 is a little different in that the licensor can opt-out of GPL compatibility.) More here: http://www.gnu.org/licenses/license-list.html http://www.gnu.org/licenses/license-list.html Generally speaking, if the software is free and not subject to copyleft or a choice-of-law provision, there is probably nothing to stop users from redistributing it under the GPL.