[License-discuss] dual licensing and the Open Source Definition

Engel Nyst engel.nyst at gmail.com
Wed Dec 18 19:48:48 UTC 2013

On 12/17/2013 09:34 PM, zgilboa at culturestrings.org wrote:
> On 12/14/2013 02:21 PM, Engel Nyst wrote:
>> It's quite common place today; I say weird not because it's
>> uncommon (it's not) but for several other reasons, among which one
>>  similar to yours if I understand you correctly: this particular
>> dual licensing doesn't seem to serve the goals intended by the
>> license (not by OSI). Whether you consider these goals focused to
>> assure software freedom/openness or to promote alternative business
>> models.
> Indeed, the purpose of my question was to find out whether a single
> license could guarantee that the source remains available in all
> scenarios, and also ensure that using the library would be free for
> all end-users, yet entail a (one-time) charge for vendors of
> commercial/proprietary software. I think there are several advantages
> (both practical and technical) to using a single license over
> multiple licenses, but at the same time consider such advantages to
> be secondary to offering at least one license that is OSI-approved.

Please note, this is not what I said. I don't support trying to use GPL
with proprietary licenses for particular uses, one-time or not.
Businesses could and should be built without relying on (additional or
not) licenses that go back to copyright restrictions.

If one's goal is to make money by something else than donations (as you
were writing), my suggestion would be to look into ways that aren't
donations, nor relying on copyright restrictions. I gave a couple of
quick examples.

> Thank you for making so many excellent points.  The model based on a
> transitive grace period is very interesting, even though it still
> requires dual-licensing for full compatibility with other open
> source projects and libraries.  One way or the other, then, it might
> have to be a dual-licensing model that offers the GPL in conjunction
> with the license of choice...

I'd make two more notes here. First, the two "dual licensing" real-world
facts, the model you were initially referring to, and the dual licensing
in the example of transitive grace period, are, IMO, entirely unrelated,
as far as reasons/intents of dual-licensing are concerned.

The transitive grace period license seems (to me) a viable licensing
framework for who wants to make software proprietary for a while (12
months, for the first licensee/second licensor). It seemed relevant to
your intent to ask for a fee via copyright. However, this license, as
opposed to proprietary ("licensing fee for business use"), is *not*
proprietary itself, or not in my reading.

Concerning its OSI approval, you may find a lot of discussion on it
(example [1]) in the archives of this mailing list. IIRC, there have
been a lot more concerns on proliferation, practicality and
understandability on how the license works, than problems on OSD
compliance. Please check them out if you wish, though. I haven't re-read
some emails on TGPPL possibly for years, my memory may be faulty.

Dual-licensing with GPL is here for compatibility with GPL. I'd add that
there are other open source copyleft projects (and licenses) that
dual license or allow relicensing to GPL, to ensure compatibility. Most
permissive licenses/projects don't need it, but copyleft
licenses/projects need it if they want this compatibility. That happens
because GPL scope is maximum, and copyleft is usually defined as
"licensed under the same license" (so there's a conflict between such

A second note I'd make: whether this particular licensing attempt is
interesting to you or not, please note a distinctive feature it has,
opposed to dual licensing models "for business": all paths result
eventually in open source software available, and with all source,
including for downstreams. Maybe in 12 months (if the licensee chooses
TGPPL and the grace period), maybe immediately.

[1] http://ur1.ca/g7w2v


~ "Excuse me, Professor Lessig, but may I ask you to sign this CLA, so 
that we have legally your permission to distribute your CC-licensed words?"

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