Send audio to bluetooth device using AVPlayer IOS

Hi I have a video app that uses AVPlayer, I received an email from a user saying that he can no longer use his car bluetooth as I updated the app a while ago.

Now I didn't try to support bluetooth, but apparently this functionality came along with the MPMoviePlayerController I used before.

Is there a way to check if the bluetooth device is connected and send audio to it?

I saw this question but it didn't help, the volume control shows but no button lets me select the output.

Do I need to do something to use bluetooth as output?

I only tested my car bluetooth which works with phone calls as well as other apps like Viber.