While researching the licensing for SE sites, I've come across a few questions about changing the license terms (e.g. updating the CC-BY-SA version).

Let's assume there was a good but non-catastrophic [1] reason to, is it too late to practically do so? Are we "stuck" on CC-BY-SA 3.0 Unported forever?

[1] A catastrophic reason would be SE going out of business if they did not. In that case I think there'd be enough business incentive for SE to take action, and enough goodwill from a large number of regular and significant SE contributors to click however many buttons it takes to relicense their work.

  • 1
    This is a question that can only be answered by lawyers. Wikipedia has done it before though, going from GFDL to cc-by-sa. I am not sure anymore what was required to get that going.
    – Sumurai8
    Sep 5, 2014 at 14:14
  • @Sumurai8 I was thinking about what legal and software mechanisms are already in place - e.g. is it actually "3.0 or later", is there an existing profile option allowing relicensing, etc
    – lofidevops
    Sep 5, 2014 at 14:36
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2 Answers 2


More or less, yes.

Contributors retain the copyright to their content, and license it to StackExchange. There are some ambiguities as to which license is currently used that a lawyer could have a field day with (you could argue that the content is CC-BY-SA-2.5 as linked in the terms of service, CC-BY-SA-3.0 as linked in the page footers, or any CC-BY-SA since no version number is specified), but changing the license of existing content requires the approval of the copyright holders, which would be a major operation. (Quite possibly an impossible one, in the case of anonymous users and users who have since died.)

The license for new content can be changed at any time, but as a practical matter, any new license would need to be compatible with the current license (since answers tend to build on each other), and the site would need to track which license any given piece of content was under.

Wikipedia was able to change from GFDL-1.2 to dual GFDL-1.3 and CC-BY-SA-3.0 because Wikipedia's license statement included an "or any later version" clause, and GFDL-1.3 included a clause permitting GFDL-1.2 collaborative websites to be dual-licensed under CC-BY-SA-3.0 or later. The StackExchange sites do not appear to have such a clause.

  • any comments on what I've found about CC-BY-SA later and compatible licenses?
    – lofidevops
    Sep 9, 2014 at 10:27
  • 3
    @d3vid, the upgrade mechanism appears to apply only to derivative works; you can't change the license version on the original material. To what extent this is an actual barrier to upgrading is something a lawyer (or possibly the court system) will need to answer.
    – Mark
    Sep 9, 2014 at 17:38
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    hmm we need ianal.stackexchange.com
    – lofidevops
    Sep 9, 2014 at 17:46
  • Dead users can still potentially have their work re-licensed because there are always inheritors (like family) who could legally approve it. For anonymous contributions, if no one can claim rights on it, then the content becomes de facto do-what-you-want-with-it as... no one can claim rights on it.
    – Cœur
    Sep 6, 2019 at 15:22
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It is not too late to change to another compatible license. More to the point, it is possible to use SE content with a compatible license even if the license notice on the site does not change.

Later versions of CC-BY-SA

Starting with the release of the 2.x license suites, CC expanded compatibility by allowing contributions to adapted material to be created under the same or later version of the original license, including other ported versions of the same or later version of the license.

(from Compatibility mechanism in BY-SA licenses on the CC wiki)

In other words, despite the 2.5 / 3.0 ambiguity, all the SE content could be:

  • explicitly relabelled on the site as CC-BY-SA 4.0 (or later)
  • used under CC-BY-SA 4.0 (or later) without explicit relabelling

Other compatible licenses designated by CC

The 3.0 Attribution-ShareAlike goes one step further, by allowing those contributions to be licensed under under a “Creative Commons Compatible License,” defined to mean licenses approved by CC as essentially equivalent to the 3.0 Attribution-ShareAlike license. (ibid)

In other words, under CC-BY-SA 3.0 or later (which applies even to the 2.5 content, see above), all SE content could be used under a CC-approved compatible license without explicit relicensing.

The caveat to this is that no compatible licenses have been defined (yet).

Non-compatible licenses

For example, FDL 1.3 or CC-BY-NC / ND. No, changing would not be practical. See Mark's answer for details.

(Note that FDL may become compatible in the future. See Why does Stack Exchange not dual-license content under FDL? )

  • 5
    You can only upgrade the version for "adapted material", not the original, nor collections thereof.
    – OrangeDog
    Sep 8, 2019 at 12:18
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    Downvoting because you're quoting the wrong part of the license. This only applies to derivative works.
    – jhpratt
    Sep 27, 2019 at 16:32

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