I think we need clarity of this item from the FAQ:
DO I NEED TO DOWNLOAD SPECIAL VERSIONS OF A TITLE TO SEE DOLBY VISION?
Yes. To take full advantage of Strato V’s Dolby Vision playback capabilities, a Dolby Vision version of the movie must be downloaded to the system. In almost all cases, at time of purchase, the Kaleidescape store will automatically detect your Strato V player and download the correct Dolby Vision version.
When configured to minimize display mode changes, Strato V will convert HDR10 content to Dolby Vision format for playback on a Dolby Vision display.
If a Strato V player is connected to a display that only supports HDR10, then the player will play back in HDR10 on that display.
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To me, the above infers that a Strato V, when connected to an HDR only display, can play the DV file in HDR. If this is not the case, then that last line really needs to incorporate a reference to an additional download.