[gnu.org #209128] Does the "GPL version choice" impact GPL-compatibility?
Response from David Turner, forwarded with permission. As noted, please
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I've split this from the existing thread so it doesn't get lost in the
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A careful reading of section 9 should address these concerns:
If the Program specifies a version number of this License which applies
to it and ``any later version'', you have the option of FOLLOWING THE
TERMS AND CONDITIONS either of that version or of any later version
published by the Free Software Foundation.
This clearly permits works under v2plus to be combined in any way with
v2only works. The distributor of the end work can do so by following
the terms and conditions of GPL version 2. That parts of the work (and
the work as a whole) can only be distributed under version 2 of the GPL
does not constitute an additional restriction under section 6 of the
GPL, because section 9 is part of the GPL.
If you're distributing a modified version of a v2plus file under v2only,
you should change the notices in the file. People who want the v2plus
version (without your improvements) can probably find it. You should
not change v2plus notices on files that you have not altered -- it's
true that in this context, they're v2only, but when distributed
separately, they're v2plus. You're not a copyright holder on these
files, so you would be falsely describing the copyright holder's actual
It may be the case that some people, who wish to distribute under v2plus
terms, will reject modifications which are under v2only. This is a
shame, but the alternative (that is, that all works derived from v2plus
works must be v2plus) effectively creates two incompatible licenses.
>From an ethical perspective:
I (personally) am a licensor of a few works under v2plus. I would be
disinclined to accept patches under v2only. It's simple politeness to
go with whatever license upstream is using, so long as it's not heinous,
or to choose a less restrictive license. So, I would see nothing wrong
with contributing v2plus code to a v2only codebase.
On Wed, 2004-08-25 at 18:12, Glenn Maynard via RT wrote:
> On Wed, Aug 25, 2004 at 04:40:34PM -0400, Brian Thomas Sniffen wrote:
> > And my changes do specify a version number.
> Hmm. It comes down to compatibility again. This isn't immediately
> clear to me either way from reading the license; instead of trying
> to interpret, I'm going to punt the question.
> email@example.com, a question (in a few forms):
> Is it valid to combine GPL work placed under "GPL version 2" with one
> under "GPL version 2 or any later version"? That is, do versioning
> choices impact compatibility (when the versions overlap)? Are all future
> modifications bound to give the same permission to upgrade the GPL?
> It seems like an added restriction; "version 2" implies "no upgrades
> allowed". It would allow a third party to prevent his modifications
> from being used in the original work, if the original authors want to
> maintain "or any later version", by not granting that permission in his
> modifications (which is exactly something GPL#6 seeks to prevent).
> If not, it's worse: GPL software, under a canonical interpretation, would
> be incompatible with other GPL software due to differently exercised
> license options. As many people do, in fact, omit "or any later version",
> it would probably be a real-world problem.
GPL Compliance Engineer
Support my work: http://svcs.affero.net/rm.php?r=novalis&p=FSF
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