I am currently at 2-1/25. What changes will I notice if i install an update?

I presume that all the updates on here are firmware as opposed to map update - ie it will alter the interface etc but will not change the map I see. What differences will there be?

Also - I don't seem to be able to get the TMC to work. TMC is printed in black. According to a map I saw, my area has only limited TMC coverage (so perhaps only major roads).