His sig says C220 w204, so it's NTG4 if the Comand screen pops out from the top of the dash (pre facelift) or NTG4.5 if the screen is always visible (post 2011 facelift).
If pre-facelift, you also have to lok at the build date as cars built pre 11/2008 have a nav partition on the HDD that will only take updates to V12 2014-15, attempting to install a later update will cause major problems.
Search on here and you'll find instructions to access the engineering menu on Comand and find out what is currently installed - be careful, do not change anything in the engineering menu!
Comand.co.uk (sponsors of this forum) are the acknowledged experts on stuff like this.
So, like me you have an NTG4 with the small HDD partition. Comand.co.uk reckon they have a disc that will sort that problem and install the up to date maps, AFAIK they have bench tested it but not installed in a car yet - and it's not cheap! Other than that, your only option is to buy V12 DVD's (genuine ones!) which can often be had quite cheaply on the forums or Ebay (search EU not just UK).