[Interest] Available versions to QML import in older Qt releases?

[Jason H]

> I'm working on a product based on Ubuntu 15.10, where Qt 5.4.1 is the
> packaged version (I know a more recent Ubuntu is soon to be released,
> and an LTS at that, but we're on this version for now).
> 
> Is there an online way to find out which versions of packages I can
> import from the QtQuick 2 that comes with 5.4.1, short of downloading
> the offline documentation?
> 
> Experimentally I've deduced that
> 
> QtQuick 2.4
> QtQuick.Window 2.2
> QtQuick.Controls 1.3
> QtQuick.Controls.Styles 1.3
> QtQuick.Layouts 1.1
> 
> are the versions available in 5.4.1 for the packages I'm using, but it
> would be great if there was a way to look up/confirm this quickly.
> 
> I know there's older Qt docs at http://doc.qt.io/archives/ , but it
> only stretches one version back, to Qt 5.4.

QtCreator seems to know what versions are installed, and suggests these via auto-complete. 

Hijacking this a bit, what is the behavior of imports when a later version is present? What am I missing when my script does an import of a previous version? Am I not getting bug fixes? It would be nice to know what the deltas are between versions, as well as a wildcard for importing whatever the latest and greatest is. Kind of like node's npm where you can spec a version and anything after that version.