How to control tv volume from iPhone apple tv remote
Using AppleTV remote app on my IPhone 7+ on IOS10.2.1
How do I control the TV volume using the app?
iPhone 7 Plus, iOS 10.2.1
Receivers with HDMI-CEC volume support let you adjust volume with the volume buttons on the side of your iOS device. You just need to plug your Apple TV directly into your receiver (not into your television).