There are two software versions of the colour screen, one up to mid 2004 and one after. You can find out what yours is by going into service mode on the unit.
(switch on the Connect and make sure that the Radio is working; if it is not, switch it on by
pressing the AUDIO button
press the MAIN button
press the right knob/button to display the main menu shown in the figure.
press the AUDIO button for a few seconds until the words 'AUDIO OFF' appear
enter the assistance password by pressing in sequence the buttons 1-2-3
press the right knob/button to confirm; this gives access to the 'Assistance' menu)
The pic on the right is the older software version, the one on the left is the newer one.
The first version is 23.00 to 26.16, the later versions are labelled 4.00 to 5.02. (latest version as far as I m aware, or maybe a newer verion has just come out if you ve just had yours updated by a dealer)
Only the later versions (04.00 on) can be upgraded to play mp3s.
It is possible to use the cd player and nav at the same time but you have to plan the route first (according to the manual).
It wont play DVDs though.
If you dont have an iPod/iPhone then you can get a Dension or Loudlink for it-these are "virtual" CD changers that have SD card slot (and USB on the Dension)-the unit controls them like a normal CD changer.
You can update the software yourself, by downloading the ISO, burning it to a cd and reflashing the unit. For more info see this thread-there are links to ISOs for both versions, if theyve expired I have copies: