[Interest] Qt free software policy

Tuukka Turunen tuukka.turunen at qt.io
Wed Aug 14 20:36:45 CEST 2019


Hi,

Qt’s approach to open-source is publicly described, but perhaps a bit hidden, check for example:

  *   Section 3 of https://www.qt.io/faq/
  *   https://wiki.qt.io/Qt_Project_Open_Governance
  *   https://www.qt.io/licensing/

We have been releasing new add-on modules under GPLv3 and commercial licenses with intention of growing the adoption of commercial license for those making closed-source applications with Qt. Alternative for using GPLv3 and commercial would be to only offer these add-ons separately under a commercial license, which would mean not even those who are ok with GPLv3 license could use these add-ons. Some of such components do exist, but most of our code is available under an open-source license as well.

At the same time we have developed a lot of new functionality, done a lot of improvements, and fixed a lot of bugs in functionality available also with LGPL license. This is a big investment, which directly benefits all Qt users whether they distribute their applications under LGPL, GPL or commercial license. Just look at the amount of new and changed code and you can see that the LGPLv3 parts are clearly not some legacy functionality, but very actively developed areas of Qt.

Yours,

                Tuukka


From: Interest <interest-bounces at qt-project.org> on behalf of Benjamin TERRIER <b.terrier at gmail.com>
Date: Wednesday, 14 August 2019 at 19.21
To: qt qt <interest at qt-project.org>
Subject: [Interest] Qt free software policy

Hi everyone,

Since we are talking about the future of Qt these days, I would like
to know The Qt Company free software policy with Qt.

Today, most of Qt modules are released under 3 free software licenses: LGPLv3,
GPLv2 and GPLv3. Some modules are released only under GPLv3.
If my memory is good, these GPLv3-only modules are the ones which used to
be commercial-only modules (like Qt Charts).

However, it seems to me that most, if not all (except Qt 3D), new Qt modules
are now being released only under GPLv3:
 - Network Auth
 - WebGL
 - WASM
 - Http Server
 - Lottie
 - Quick 3D
 - MQTT

I understand that The Qt Company is only obligated to release new modules
under GPLv3 (because of the KDE agreement).
I understand also that The Qt Company business model is selling Qt licenses
and has no direct financial interests in releasing Qt under any other license.

So I can understand that some modules, in particular those valuable for wealthy industrial companies,
are only released under GPLv3.
However, for some modules like HttpServer, it seems to be an odd choice. There are plenty
alternatives available under LGPL or more permissive licenses, so I do not see what
would be the loss of releasing it under LGPLv3.

Also the fact that those modules are GPLv3 only is a problem when developing with other
components that are GPLv2 only (and not GPLv2+).

So I would like that someone could officially confirm if all new modules will be
released under GPLv3 only. Or if it is something that is decided on a per module
basis.

I believe that Qt users and contributors deserve to know what it The Qt Company
view on this.
Using an LGPLv3 framework is not the same thing as using a GPLv3 framework
where some historical parts are available under LGPLv3 and all new features will be GPLv3 only.

BR,

Benjamin


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