Q: Bluetooth not working since ios10 update

Revert..no, that is not supported.

Try a reset by holding the power and home keys down until the Apple logo appears.

Barry

Remove the devices from the list of devices on the phone. Remove the iPhone from the vehicle list. Turn Bluetooth off on the phone. Power the phone off/on. Place the vehicle back into discovery/pairing mode. Turn Bluetooth on for the phone, and you should get the prompt to continue the connection. For the other devices, which you do not list what you are referring to, make sure you put them into discovery/pairing mode again to connect.

What type of vehicle are you trying to connect to? I've not experienced any issues with my connections on a 2012 Hyundai. Can you reset the vehicle's system? On the phone you can try going to Settings>General>Reset>Reset Network Connections.

Do you have any other Bluetooth devices to test with?