Roku sticks are RF only, no IR at all, at least for the roku commands they still use IR to control your tv. Roku just released the Streaming stick 4k:
https://www.roku.com/products/roku-streaming-stick-4k
Although if you were to unplug the roku stick from power, its remote would start emitting roku IR commands instead of wifi, until the stick was plugged back in.
Edmund
Roku Community Streaming Expert
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