I wish I had not updated! Following my update from 13.4 to 13.4.1, Bluetooth audio support in my car (Ford SYNC) stopped working! On my phone, SYNC does NOT show as connected, and when I initiate Bluetooth audio, it can no longer find my phone (can't make it connect from phone, can't connect from car). HOWEVER... for some reason, I can still make hands-free calls and access calling features (such as phonebook) which uses BT!
This is very confusing. While I'm thankful that the hands-free calling still works, I'm very frustrated that the audio streaming seems to have broken. I've tried restarting my car (obviously), restarting my phone, turning BT off/on, etc., but I still cannot get audio connected. The only thing I have not done is a 'forget' and re-pair, because I don't want to lose the ability for my phone to work.
If anyone else has experienced this, please let me know the fix!