To change the device mode between Winodws and Mac mode:
This applies to all devices that have Bluetooth - typically with a rev. 4.0 sticker.
The combination of buttons is DPI (cursor speed) + Paste.
While holding down the DPI button, you can now press the paste button to change mode of the device.
Windows mode: Press paste 1 time, and the first LED light from the left will light up.
Mac mode: Press paste 2 times, and the second LED light from the left will light up.
HID mode: Press paste 4 times, and the fourth LED light from the left will light up.
Choose the mode fitting your operating system and you are good to go.