I have the older Roku Ultra 4K model 4640 specifically because it's the only one with an actual optical (toslink) and Dolby Digital encoder.
Can anyone confirm that this specific model can output HDR and not just normal 4K SDR ? Will it do HDR10 and Dolby Vision or just one or the other ? Are there any other limitations ?
It does HDR10; no mention of Dolby Vision.
Hardware specifications | Roku Developer