[Zope-dev] ZPL and GPL licensing issues

[Gregor Hoffleit]

On Wed, Jun 20, 2001 at 04:50:33PM +0200, Morten W. Petersen wrote:
> we @ thingamy are considering changing our license to a ZPL-ish one [1] to
> better serve our clients' needs.  However, some of the (Zope) products
> we've developed may need to rely on GPL'ed code, or needs to be
> incorporated within it, and the 'obnoxious advertising clause'
> seemingly puts a stop to it..
> 
> The ZPL is listed as a license incompatible with the GPL, but it doesn't
> really say clearly what the reason is, as far as we can figure, it's
> because of the advertising clause.
> 
> Anyways, I'm wondering if any of you have encountered the same issue
> developing Zope products and any solutions towards it.

I recently asked RMS about this exact question. He studied the license and
said that another problem field is that the license is not clear whether
modified versions can be distributed in binary form (paragraph 7 of the
ZPL).


I hope he doesn't mind me quoting the second part of his exact words:

    "... If the Zope developers are willing to make just one change, I hope
    they will clarify section 7 to clearly say that modified binaries may be
    distributed if labeled as unofficial.

    If they would like to make the license GPL-compatible as well, that
    would require a few more changes:

    * Section 4 would have to go.

    * The license would have to allow distribution of modified sources, not
    just source patches.

    * Instead of saying that modified versions have to be "labeled as
    unofficial", it would have to say they must be labeled as modified and
    by whom.  (That is what the GPL requires.)

    If they don't want to make that much change, well, being incompatible
    with the GPL is unfortunate but not disastrous.  But I hope they will
    clarify the issue of modified binaries, because that issue could be
    disastrous.

    Please invite them to contact me directly to talk about this.


I forwarded that mail to zope-license@zope.org, but I have no idea if
consultations are going on between them.


    Gregor