Power off with tv

I would like to be able to turn off the cable box when I turn off the tv. About a year ago I found in the labs section that there was a test feature that used feed back through the hdmi cable. After a recent update I noticed my cable box no longer cycles on/off with the tv. I went to the labs section and found that test feature is no longer available.

Please re-enable this feature. 

Thank you. 

Robert Page