Suppose person X writes some library foolib, licensing it under the 3-BSD license.

Person Y now takes the foolib sources and develops it further, making significant changes: More functionality, changes to existing API, partial rewrite of the internals etc.. But of course, it is still an evolved and changed foolib.

Can person Y release their modified library under another license? e.g. GPL or LGPL? If so, what is the threshold to the amount of change necessary so that the original 3-BSD license doesn't "stick" to it, and its legal use is restricted to the terms


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    How about this? Can one take BSD licensed code and distribute it under GPL? (Note that this is not the same question you link to above.)
    – MadHatter
    May 1 '21 at 5:08
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    Thanks for nominating this for reopening. The issue, to my mind, is that it's already completely answered within the three answers linked to, thogh I agree that none of them is a precise duplicate. If you have any remaining question that's not addressed by those three, please edit this question to reflect it.
    – MadHatter
    May 3 '21 at 6:21