In prior Qt releases, all the Qt Quick elements were available in the Qt namespace. Starting with Qt 4.7.1, the elements are also available in the QtQuick namespace, which improves naming consistency, and allows the development of Qt Quick to occur at a faster rate than Qt's usual minor release schedule.
The change for developers is very simple - where you previously wrote import Qt 4.7, just replace it with import QtQuick 1.0, like this:
import QtQuick 1.0 Text { text: "Welcome to QtQuick 1.0!" }
import Qt 4.7 continues to work so existing applications wont break even if they aren't updated, but it is recommended that all import statements be modified to the new form.