XiD-P audio

I was recently notified that "one or more of your TV boxes needs to be replaced".  I 

ordered the replacement equipment and received two XiD-P boxes to replace my two existing 

RNG200N boxes.

My audio receiver does not have an HDMI input; I am connected to the RNG200N via the 

Optical S/PDIF.

Is there alternate equipment that will supply this need, or am I expected to buy a new 

surround sound receiver to allow hearing my TV?  What happens if I do not "upgrade"?

Thanks in advance.