Raising Qt requirement to Qt 5.4

[Aleix Pol]

On Wed, Mar 16, 2016 at 1:13 PM, Martin Graesslin <mgraesslin at kde.org> wrote:
> Hi all,
>
> with todays release of Qt 5.6 I suggest that we raise the minimum Qt version
> requirement to 5.4. This would mean the latest three releases are supported.
>
> The important new features in Qt 5.4 in my opinion for frameworks development
> are:
> * QSignalSpy(const QObject *object, PointerToMemberFunction signal)
> * Q_LOGGING_CATEGORY(name, string, msgType)
>
> Which are already used in many frameworks and currently ifdefed.
>
> Opinions?

I'm not sure, Qt 5.4.0 has only released 1 year ago, doesn't sound
like a lot of time, I'm unsure what people are using though.
https://wiki.qt.io/Qt-5.4-release

Aleix