The issue is that as a pass through (meaning when audio comes to the TV through HDMI from a connected device, such as a Roku, and is rerouted to the output), it only outputs stereo. It outputs 5.1 when it is not acting as a pass through (when hooked up to an antenna or from its built-in streaming apps). My TV is only 3 years old. Apparently the challenge is that the TV would need to take the input audio and transcode/compress it before rerouting it to the output. It seems that few models of TVs of that era had that capability. I suspect more models of the current generation of TVs have that capability, especially ones made by LG.