Version 4-1/71 is the highest. Though, we do not know yet what the differences are between 4-1/70 and 4-1/71. Plus, I do not think that US dealers have received 4-1/71 yet, so they probably would not be able to upgrade you. I would just enjoy the version you have.

Take a slow read through the navigation manual, because that is the best place to start. Then, after you tinker with the system for a little while and let it "navigate" you, you will get a very good feel for it. There is not a lot to add or customize.

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SOLD
2000 E38 750iL Highline Edition, Upgraded with the lastest 2006 X5 Electronics
MKIV Navigation, 16:9 Display, Bluetooth, TV/Video with Backup Camera, Sirius, and Aux Input