This is Qt version 4.7.0. Qt is a comprehensive cross-platform C++ application framework. Qt 4 introduces new features and many improvements over the 3.x series. See http://qt.nokia.com/doc/latest/qt4-intro.html for details. The Qt 4.x series is not binary compatible or source compatible with the 3.x series. For more information on porting from Qt 3 to Qt 4, see http://qt.nokia.com/doc/latest/porting4.html.