Error 404 when using the "Select version" drop-down menu in module doc pages

This error applies to all module pages. One example below:

The QtMultimedia module page was relocated from
http://qt-project.org/doc/qt-4.8/qtmultimedia.html
to
http://qt-project.org/doc/qt-5.0/qtmultimedia-module.html

However, the "Select version" drop-down menu doesn't know this, and users can't switch between the Qt 4.x and Qt 5.0 module pages