Currently an application depending on a specific version of Qt cannot detect at install time which version of Qt is installed on device, and eventually install some specific components depending on this information (e.g. install QML based UI if Qt 4.7 is available or widget based UI if not).

Also, if an application does not use smart installer but instead embeds qt.sis, it will not be able to detect which version is installed on device and unintentionally downgrade the runtime.

My suggestion is for Qt to adopt this recommendation: http://wiki.forum.nokia.com/index.php/TSS001331_-_Enforcing_version_checking_of_embedded_SIS_file and include the following statement in next release's PKG (presuming 4.7.2)

+(0=400700200)

(or similar) allowing developers to start querying package's version.