[Development] Updating the licence policy for Qt Project

[Knoll Lars]

Hi,

As you've seen in my blog post on Wednesday, Digia has decided to add
LGPLv3as a licensing option to all of Qt. This decision has been driven
by several factors as explained in my blog post. Digia could do this
decision due to it's rights to the code through the CLA. Having the option
to add the license due to the CLA is in my opinion very beneficial to Qt,
as we can react to changes in the world around us.

The changes consist of two main parts.

First of all, the addition of LGPLv3 as a license to all existing Qt
modules. All these modules have been so far licensed under LGPLv2.1, GPLv3
and commercial (with the exception of QtScript and QtWebKit that do not
have commercial due to external LGPLv2.1 dependencies). The new set of
licenses will now be LGPLv2.1, LGPLv3 and commercial. LGPLv3 is a strict
superset of GPLv3, so the change only gives additional rights to Qt users
otherwise doesn't change anything. It also now allows you to use Apache
2.0 licensed code together with Qt if you use Qt under the LGPLv3. So I
believe this to be a very good change for the Free Software community.


The second part is the introduction of new modules licensed under LGPLv3,
GPLv2 and commercial. GPLv2 is mainly there to make it possible for
existing GPLv2 only applications to use these new modules. In my opinion
it's also a good change for Free Software, as LGPLv3 is a stronger
copyleft license than version 2.1. In addition, Digia does not want to
license some of it's code under version 2.1, but is willing to give it to
the community under LGPLv3.

The goal here is that adopters of those new Qt modules will have to abide
by the terms of the LGPLv3, which require the ability to replace the Qt
that is on the device on the actual device, thus creating an open
ecosystem for application developers, or instead purchasing a different
licence from Digia, which results in investments in Qt.


There have been lots of talks within Digia about this change. We have also
talked with some of the key contributors and partners inside the Qt
ecosystem as well as the KDE Free Qt Foundation, and overall gotten a very
positive response to our intentions, leading to the announcement of the
change two days ago.


With this in mind I would like to now formally adopt and embrace these
changes to how Digia will release Qt as changes to the licensing policy
within the Qt Project as well. There are basically three changes:

1. Modules that are part of Qt 5.3 are now licensed under LGPLv2.1, LGPLv3
and commercial
2. New modules that get added to Qt Project from now on can be licensed
either under
    * LGPLv2.1, LGPLv3 and commercial or
    * LGPLv3, GPLv2 and commercial
    * LGPLv3 and commercial

Note: with the adoption of LGPLv3, Qt is now able to link to code under the
Apache License v2.0 (previously, that was only possible by accepting
LGPLv2.1's provision of using the terms of the GPLv3). Therefore, it is now
possible to have third-party code imported into the Qt repositories that
are LGPLv3/commercial only under that license. As with any import of
third-party code, approval from the Chief Maintainer is required.

I hope that everybody agrees with these changes. If you have concerns or
disagree with this change, please let me know.

Cheers,
Lars