[Interest] Qt free software policy

Konstantin Tokarev annulen at yandex.ru
Wed Aug 14 20:15:21 CEST 2019

14.08.2019, 21:04, "David M. Cotter" <dave at kjams.com>:
>i’m ALLOWED to use the free version, right? or did i misunderstand how LGPL works?

You are allowed to use it if you comply with LGPL terms.

In case new modules are licensed as GPL-only and you don't want/can't comply with GPL,
you won't be allowed to use that new modules (note that there are certain cases when
complying with GPL does not require you to releasing your code, for example if your
application runs on the server controlled by you and users interact with it only by means
of network connection).

Even in the case (very unlikely) that existing Qt modules are relicensed to GPL-only, you
can continue using previous version under LGPL terms, or make a fork.

>> On Aug 14, 2019, at 10:11 AM, Vadim Peretokin <vperetokin at gmail.com> wrote:
>> Sorry but I'll ask the obvious question: you bet your entire business without paying for a license?
>> Have I misunderstood you?
>> On Wed, 14 Aug. 2019, 7:01 pm David M. Cotter, <dave at kjams.com> wrote:
>>> +1 on this
>>> i am in the process of porting my legacy project to Qt and am afraid that i’ve made the wrong choice.  i’m just one guy and i bet my whole business on the availability of what  i need from Qt under LGPL
>>> i’m already using a third party HTTP server so i’m not affected by this but it’s a worrying sign. I too agree that the HTTP server really should be LGPL.
>>> What’s going to happen? It’s taken me over a year’s worth of work to get this far with Qt and i’m only half done. did i make the wrong choice?
>>> -dave
>>>> On Aug 14, 2019, at 9:18 AM, Benjamin TERRIER <b.terrier at gmail.com> wrote:
>>>> 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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