Hi folks,

Some time ago we already had a discussion about possible license
changes. See http://lists.roundcube.net/mail-archive/dev/2010-01/0000022.html
to refresh your memory.

Now, almost two years later we came to the conclusion that it's time to act.
But let me describe our thoughts a bit more:

Current Situation
=================

Roundcube has inherited and built upon code from a variety of
projects, allowing it to grow quickly to the solution we all love
today. In doing so, it has effectively also inherited its licensing
policy from projects which were not handling these issues as carefully
as one might have wished.

These projects have often done a "licensed under the GNU General
Public License (GPL)" without an explicit version. Sometimes this
statement was accompanied with a link to a web page, most importantly
http://www.gnu.org/licenses/gpl. This link was pointing at version 2
of the GPL, but it is the link that always leads to the latest
version, so right now is pointing to GPL version 3. And so did
Roundcube itself.

This, and the provisions in GPLv2 which say that you may at your
option choose a later version if there is no explicit version
mentioned means that right now Roundcube is "GPL v2 or v3, either may
be binding for you depending on how you got it" and would *not* allow
proprietary extensions and modules and may or may not allow
proprietary skins, depending on your interpretation.

This is clearly not a perfect situation and it doesn't reflect the
consensus within the Roundcube community (especially after the last
licensing discussion) that proprietary modules (plugins) should be
allowed, as should be proprietary skins. We meanwhile have specified
Version 2 in our source but some links still point to the above
mentioned URL which now shows Version 3 of the GPL.

So it would make a lot of sense to clarify this explicitly.

At the same time, the possibility of Roundcube being under GPLv2
blocks some innovation we would like to do for future versions, such
as for example inline ODF support through WebODF, which is licensed
under the GNU Affero General Public License (AGPL) Version 3.

Background information for the interested
=========================================

* GNU General Public License (GPL) Version 2:
 https://www.gnu.org/licenses/gpl-2.0.html

* GNU General Public License (GPL) Version 3:
 https://www.gnu.org/licenses/gpl-3.0.html

* A Quick Guide to GPLv3:
 https://www.gnu.org/licenses/quick-guide-gplv3.html

* GNU Affero General Public License (AGPL) Version 3:
 https://www.gnu.org/licenses/agpl-3.0.html

* Frequently Asked Questions about the GNU Licenses:
 https://www.gnu.org/licenses/gpl-faq.html


Proposed license clarification
==============================

Because of the incorporated numerous other components, the only
options for licenses
are in the GNU GPL family, namely GNU GPLv2, GNU GPLv3, GNU AGPLv3.

In order to become license compatible with some of the technologies we
would like to be able to use in order to improve Roundcube, we should
at the very least choose GNU GPL version 3.

We could also choose GNU AGPLv3, which would provide more rights to
the users of Roundcube. It would mean that all users have the right to
obtain the code of the instance that is providing their service (minus
the additional modules, of course).

It would also ensure that modifications on the basic Roundcube
codebase will have to be made available as soon as the are being used
to provide services over the internet, not just when they are
distributed in other ways.

This is the first choice we have.

Personally I'm okay with either, but as the recent discussion showed
us, there are some arguments against the AGPL option. I would,
however, in any case suggest we explicitly leave the "or any later
version" default in, so future license updates won't require us to
look at this again.

Secondly, if we want to allow proprietary modules and skins, which has
turned out to be a major concern of our "users", we should add the
explicit permission to create modules under any license, including a
proprietary one, which can be done through the following exception to
GPLv3 or AGPLv3:

    This file forms part of the Roundcube Platform for which the
    following exception is added: Plug-ins and Skins which merely
    make function calls to the Roundcube Platform, and for that
    purpose include it by reference shall not be considered
    modifications of the Platform.

    If you wish to use this file in another project or create a
    modified version that will not be part of the Roundcube Platform,
    you may remove the exception above and use this source code under
    the original version of the license.

The first paragraph provides the permission.

The second paragraph allows re-use of Roundcube's code in other
projects without the additional permission. Otherwise it would be too
easy to circumvent the license and re-use may be limited by the
licenses of the projects that wish to re-use code.

The Way forward
===============

Because the Copyright in Roundcube is not consolidated, making these
updates requires the agreement of all contributors to Roundcube.

So if you have in the past contributed to Roundcube, we would very
much like to ask you for your explicit agreement with this path
forward and your preference with regards AGPLv3 / GPLv3, and whether
you would exclude one or the other, and for which reasons.

We believe this primarily represents a clarification and an adjustment
to what we practiced over the past years, and we hope that you will
also see it that way.

But of course we cannot force anyone to agree, so for those who prefer
to have their code removed from Roundcube rather than agree to the
update, please let us know.

Timing
======

This will not affect the 0.7 release, which will still take place
under the somewhat fuzzy licensing situation, but we'll want to apply
this to HEAD so we can make sure all code is properly updated and
conflicting code replaced before the 0.8 release.


Please let us know, what you think about this proposal.

Best regards,
Thomas