This will permit to display notification in native notification center on macOS 10.8+.
Good to know (http://blog.qt.io/blog/2015/05/26/qt-4-8-7-released/):
- Qt4 support ended on December 2015
- macOS support is bad, Qt5 fully support macOS functionalities
- no more Qt4 support on Ubuntu and Debian based distributions since may 2015
Also, in recent versions:
- a lot of bug fixes
- less memory footprint
In fact, we could follow the Qt development cycle (https://wiki.qt.io/Qt5Releasing) meaning we could upgrade to Qt 5.8.