At least for iPhone users there is an update in the app store. It says the update enhances current features. I haven't checked it out yet.
only change, that I can see is it connects a little more consistently when using it via a cable connection on my c4.
I upgraded the iphone app and I don't see any difference in how it works with the car apps. I don't have the newest car software yet, though.
I had 1.7.4 version and yesterday i got an email from my dealer that they got the flash drive for the new version. So I went in and got it updated to 1.8.4 last evening and still no luck with the Entunes - Iphone4 - bluetooth connection. It works fine over the USB cable though like before.