1. Is it a GPL-only thing or can I use this formulation with any license, like "MPL 2 or later"?
  2. Does it mean that in case versions 1, 2 & 3 of license are available, "version 1 or later" effectively licenses the project under all 3 of them?
  3. Can I formulate it so only the latest version of license would apply at any given time? Does it change with the condition of including license text?
  • @TechnikEmpire My answer is not "you can do whatever you want." I clearly say that you cannot change the license of something already distributed. What I do say is that, generally, you can release something under multiple licenses. Jul 31, 2016 at 3:08
  • Comments removed. Remember to Be Nice.
    – ArtOfCode
    Jul 31, 2016 at 17:48

1 Answer 1

  1. Adding a statement of "or later" to your license notice effectively dual-licenses your project, so yes, in general, you can do this. But Technik Empire raised a good point that future versions of the license may not be compatible. For example, if your GPL v2 code depends on some other GPL v2-only code, then you couldn't upgrade yours to GPL v3.

    Whether you would want to when you don't know the terms of future versions is another question. Licenses sometimes change in substantial ways. The GPL-3 has changes which many people care a lot about, and later Creative Commons licenses change how attribution must be made. If you're happy enough with a license to choose it, then I'd recommend just sticking with it. You can always reevaluate and explicitly dual-license your project if the license is revised in the future.

  2. Yeah that's right, it is dual- (or multi-) licensed under all those licenses.

  3. You can't change the license of something which has already been distributed. If someone received it under version 2 and wants to use it under that license and not version 3, they can. If you want to publish something only under the latest license, then don't publish under a "or later" clause, instead just update the license when a new version is released.

  • 3
    Some licenses (e.g. MPL 2.0 section 10.2, CeCILL Article 12.3) make the choice of later versions for you. Be aware of that when you choose to use them.
    – EMBLEM
    Jul 29, 2016 at 1:39
  • This generally answers my question, but I would like some clarification on point 3 - what I ment is stating only the latest version, without any "or". In such a way that even yet unreleased version would exclusevily apply to present project in the future. Jul 29, 2016 at 2:31
  • Regarding your & @EMBLEM's note on possible changes IMO choosing a license of a particular organization is a high enough level of trust to be somewhat sure in future edits. Jul 29, 2016 at 2:33
  • @Zero licenses must be irrevocable to be Free/Open Source. If you download a project under version 2 then you must be able to use that version of the license for forever. Jul 29, 2016 at 3:24
  • @Technik I wasn't proposing editing the license file or text. And yes, future versions may be incompatible, which is why I said you may not want to do this kind of thing. It is a risk. Jul 29, 2016 at 5:50

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