Documented UrlQueryString config parameter can't be used

QtIFW has a documented configuration parameter called UrlQueryString found here: http://doc.qt.io/qtinstallerframework/ifw-globalconfig.html

Creating an installer with the latest release with that parameter although results in an error

create Error-Exception: "Error in config.xml, line 15, column 20: Unexpected element 'UrlQueryString'."

This happens as the parameter is not in the list of known elements in settings.cpp found here: http://code.qt.io/cgit/installer-framework/installer-framework.git/tree/src/libs/installer/settings.cpp#n251