The behaviour of the Fn keys has been changed for the new devices. Now it is possible to use the functions without pressing the Fn-key. This means you only have to press F7 or F8 to dim down/up. If you press e.g Fn+F5 you receive the normal F5 function which is a reload of page. This can be changed when you press Fn+ESC, then you have the 'old' Function-Key behaviour.