Uwe Brauer <oub@mat.ucm.es> writes:
> Thanks, a couple of more question, if you don't mind:
>
>     1. Does GPL 2 or *later* mean:
>
>        a. GPL 2 and all version of that License
>           that were released  *before* GPL 2?. That seems to me the most
>           logical interpretation.
>
>        b. Or does it mean: GPL 2 and all versions that will be released,
>           *after* the release of GPL 2? That seems like a blank check to
>           me.

this was discussed during the drafting of GPLv3 a lot: a later version
means a license released after GPL 2, but only if it is similar in
spirit to the license (that’s written in the GPLv2 and GPLv3).

So no blanket permission. For any future GPL the FSF will have to make
sure that it’s similar in spirit, to GPL v2 and GPL v3, otherwise using
old code under these new licenses would risk legal attacks, and then no
one in their right mind would use those licenses.

>     2. I searched all lisp files: some have GPL 3+ some have GPL2+.
>        Is this ok, or need all files to be under the same license?

GPLv2+ and GPLv3+ are (upwards) compatible. If you have GPLv3+ files, then
the project as a whole must be GPLv3+ (or GPLv3, but please don’t leave
out the "or later", that creates a world of pain if you want to use the
later version at some point — and if history is a teacher, you will want
to).

Best wishes,
Arne
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