[Interest] Fwd: vs. Flutter

Christian Gagneraud chgans at gmail.com
Thu Feb 21 16:08:25 CET 2019

On Fri, 22 Feb 2019 at 03:56, Julius Bullinger
<julius.bullinger at gmail.com> wrote:
> On 21.02.2019 15:44, Christian Gagneraud wrote:
> > Qt is free (on mobile), free as in liberty, as long as your
> > application is free, as in liberty.
> > That's basic (L)GPL rules.
> >
> > Now there's the business rules:
> > If you want your (mobile) app to be non-free (as in proprietary), then
> > you'll have to pay the Qt company for that. Disregarding the fact that
> > you want to make money or not.
> Please do not spread this misinformation! As long as you adhere to the
> terms of LGPL, you can create non-free, proprietary and closed apps with
> Qt (or any other LGPL library for that matter). You only need to make
> sure that the user can replace all LGPL parts with their own builds.

Oops, you are right. My mistake.

And the key point is the acquisition of Qt by Nokia. Trolltech used to
publish Qt as GPL, once acquired by Nokia, Qt became LGPL.
And this LGPL stuck when Digia aquired Qt from Nokia, AFAIU. (i've
lost track of who "owns" Qt by now, so many intermediate
So yes, I agree. you can sell Qt based proprietary SW on google  play
store w/o a Qt license.
You still have to respect the Qt LGPL license, that is, if you modify
it, you need to make the source of your custom version of Qt openly
available. And this doesn't apply to you own app, thanks to the 'L' in


> The fact that the mobile OS's and app stores make it exceptionally hard
> to do that is not an issue with the license terms. If you find a way
> that enables the user to replace LGPL parts (for example by dynamic
> linking or by making all object files and linking instructions available
> on request), that's perfectly valid and legal.
> _That_ is a basic LGPL rule.
> https://tldrlegal.com/license/gnu-lesser-general-public-license-v2.1-(lgpl-2.1)
> https://tldrlegal.com/license/gnu-lesser-general-public-license-v3-(lgpl-3)
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