Burn-in advanced subtitles will drop HDR information, is it right?

[DPaO Chow]

I got a bunch of HDR and DV movies with extended subtitles. Found that if the client does not support subtitle processing natively, like Safari, Chrome or any iOS client using native player (e.g. JMP and Swiftfin), server will trigger subtitle burn-in.
Due to the burn-in process, any video with HDR will be tone mapped to sdr. 
It's 2023 now. Any solution for HDR to HDR transcoding?

[TheDreadPirate]

IIRC, version 10.9 will be able to do HDR to HDR transcoding.