Qt widgets 4.7 vs. 5.1

Qt widgets 4.7 vs. 5.1

I recently started on a new project where we will be using Qt to create
the GUI. Without getting into details, it has been mandated by management
that we use Qt 4.7. There are no valid reasons for this decision. We are
not porting any existing code to Qt 5, this is all new implementation. I
am the UI lead for the project and I need to make a case for using Qt 5.1.
I am going to explain why the concerns held by some of the engineers about
moving to 5.1 are not legitimate, but I would also like to strengthen my
case by giving specific reasons that we should use Qt 5.1 over 4.7. My
main reason behind wanting to use 5.1 is just that it's the latest version
with many improvements over 4.7. While this reason is valid, I would
appreciate it if anybody who is familiar with the differences between Qt
4.7+ compared to 5.0+ would help me come up with some specific reasons. I
have not used Qt 5 yet myself. We will be using widgets either way, not
QtQuick/QML, so please only consider differences pertaining to Qt widgets.