Hey majortom1967,
Thanks for getting in touch with us about your iPhones ability to pair with your car stereo. I can appreciate why you'd be concerned about this, so I wanted to respond with some information that might be relevant here. First off, there's a great article that offers general troubleshooting for car stereo pairing issues that you might not have seen yet: If your iPhone, iPad, or iPod doesn't connect to or work in your car - Apple Support
That said, I know you mentioned that you no longer have the option to pair the two, which sounds to me like a compatibility issue. Whenever a software update is released (for any device that receives remote updates to its software), compatibility of that device may change for some time or altogether as the associated devices need to receive updates as well. I think it'd be a good idea to check with Pioneer to see if they have any suggestions in the interim or if a software update will be coming soon.
Cheers!