Looking through ebay for a new updated navigation CD, I found this.

NEW AUDI VW RNS-D 2007 EDITION UNITED KINGDOM NAVIGATION CD | eBay

It lists RNS-d as a compatible unit but then it says not for DX Navigation.
Now I'm confused.

I thought the RNS-d was/is DX navigation?
Is there two different types of RNS?