I have an iPhone 3G that I have upgraded to iOS4. I also have an iPhone 4 on order that should ship on 2 July.
In my car I have a factory fitted stereo (Renault, Blaupunkt OEM) with USB port that worked before I upgraded to iOS4. I got track name on the car stereo display and could navigate music on the phone via the car's steering wheel mounted stereo controls etc. Unfortunately, since upgrading to iOS4 this no longer works. The car stereo reports "Cannot read this medium, please unplug".
It's not entirely clear as to whether this is an Apple issue or a car stereo issue but seems most likely to be the latter. So, I post this as a warning. If, like me, you use an iPhone for music in the car, via a dock/USB cable, make sure your car stereo manufacturer supports iOS4 (and iPhone 4) before upgrading!
In my car I have a factory fitted stereo (Renault, Blaupunkt OEM) with USB port that worked before I upgraded to iOS4. I got track name on the car stereo display and could navigate music on the phone via the car's steering wheel mounted stereo controls etc. Unfortunately, since upgrading to iOS4 this no longer works. The car stereo reports "Cannot read this medium, please unplug".
It's not entirely clear as to whether this is an Apple issue or a car stereo issue but seems most likely to be the latter. So, I post this as a warning. If, like me, you use an iPhone for music in the car, via a dock/USB cable, make sure your car stereo manufacturer supports iOS4 (and iPhone 4) before upgrading!