There is this if you can find one an do the tricky programming to get
it to work on an older car.
http://www.e90post.com/forums/showthread.php?t=687463
http://www.e90post.com/forums/showthread.php?t=1048129
There has been an issue with the newer versions of the android operating
system and bluetooth .
My galaxy s5 still works fine on android 6
I am not sure a new radio would solve your problem.