Old post but I think I can help.
I recently put a 4k tv/sofa in my computer room. I moved my Tx Nr525 from my computer to to the tv. Looking into things I found out that my receiver supports 4k 60hz but it does not support hdcp 2.2 which is the latest form of copy right protection. Basically I can push 4k 60hz through the receiver but any modern content protected by hdcp 2.2 won't work.
At first I thought I was going to have to replace the receiver then I found out about "Arc".
What arc does is sends audio from the tv to the receiver over hdmi. This removes the need to run video through the receiver. What I ended up doing was buying a 4k switch, https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
(got the 5 port version) running all of my devices into the switch, to the tv, then sending the audio from the tv to the receiver.
This worked out well. The main draw back is to get an on screen display I have to change my tv input to tv so during normal usage there is no on screen display.
I'll include a diagram to help explain things.