iDrive nav systems can only be upgraded by the dealer using BMW diagnostic system.
(except for 7-series E65).
Talk to your dealer about possible upgrades, as the whole car is done at the same time (not just the nav).
Nav software version is in the Service Menu, accessed via the iDrive controller:
To access service menu in i-drive cars:
1. From the main menu display, press the controller down for minimum 6 seconds.
2. Turn the controller 3 increments clockwise (to the right).
3. Turn the controller 3 increments counter-clockwise (to the left).
4. Turn controller 1 increment clockwise (right).
5. Turn controller 1 increment counter-clockwise (left).
6. Turn controller 1 increment clockwise (right).
7. Push down on the controller.
8. To exit the service mode, select the return arrow at the bottom on the left of the screen.



Make sure you are using the Professional map, and not the High map.