to check your current version, do the following:
1. turn the ignition key in the MAR stand - the AR logo will appear
2. Make sure the AUDIO function is active. if not, press the AUDIO button until the audio function is switched on
3. press the MAIN button
4. Push the big right button to enter the "main setup" screen
5. Now push the AUDIO button for a few seconds until you get the message "Audio off"
6. Enter the password string, which is the following keys: 1-2-3,big right button to confirm
7. there should now be a new option called "assistance" or something in the screen
8. turn the big right button towards this option and press the button to confirm
9. choose "diagnostics" by turning the right button, press to confirm
10. choose "CAN network diagnostics" by turning the right button, press to confirm
11. choose "identification option" by turning the right button, press to confirm
now check the 4th line (where it says "number SW NIT) for the last two digits
check the 5th line (where it says version SW NIT) for the two digits
if the combination of these 4 digits is less then 23(4th line).16(5th line), you should upgrade.
If the number combination is higher than 23.16, you shouldn't bother wink
to return, press "esc" several times..