In Symbian there are two new ambient light levels (KAmbientLightCloudy and KAmbientLightCloudySunny) those are not mapped in QtMobility. Currently in case of those new values QtMobility returns QAmbientLightreading::Undefined. So it could be that for example instead of KAmbientLightSunny Symbian ambient light sensor returns KAmbientLightClodySunny and because it is not know value in QTMobility it returns QAmbientLightreading::Undefined and Qt application that uses ambient light sensor does not work as expected.