The Roku Remote app only has provisions for controlling the functions that the Roku it is connected to can actually control.
If connected to a Roku streaming device the Roku remote app has buttons for Roku functions only, no buttons for the tv functions that the Roku cannot control. (If you happen to have a physical Voice Remote, the power, volume, and mute buttons control the tv directly by infrared, they don't go through the Roku.)
If connected to a Roku TV the app dies have buttons for TV volume, power, and mute functions, as they are part of the Roku TV.
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