Transcoding clarification from official docs

[nocturnalnerd]

In the official doc it reads:  

When the source video is in HDR, it will need to be tone-mapped to SDR when transcoding, as Jellyfin currently doesn't support HDR to HDR tone-mapping, or passing through HDR metadata.

This means that if the receiving device do not support the format, it will transcode the video, but it can't be watched in HDR since it will be tone-mapped to SDR?
If so, what if the receiving device supports lets say, the video format but not *.ass subtitles or 7.1 audio channel? Will I lose the HDR even if the device supports the video format?

[TheDreadPirate]

If only the audio is unsupported, the video will be copied unmodified while the audio alone is transcoded. The HDR-ness will remain intact.

In the case of clients that don't support ASS subtitles, that will require the subtitles be burned in, which requires transcoding the video, which means the HDR will be tone mapped to SDR.