BTTV 4K boxes received an update earlier this week, seemingly it enabled the introduction of BBC iPlayer 4K content to the platform. Looking very good too especially with the 50fps 10bit HDMI output selected.
thanks for the heads-up - interestingly the Wimbledon final build-up (presumably going through an HD-SDR -> UHD-HDR conversion) is looking a bit washed out on a UHD-SDR TV, though that may just be the way we've got it set up.
Also, it's a whole minute behind BBC One HD on DSat..
That’s improved from the early parts of the World Cup last year where it was up to 2 minutes behind.
On my TV the UHD HDR is ahead of the standard HD streams by a good 10-15 seconds, enough to switch to the other stream and see the same few seconds again.