It appears my Sony KD-43XE8396 is currently unsupported for BBC Iplayer 4k content (Blue Planet II trial) while many other (lesser) Sony models are. Can anyone explain why? Iplayer say support for HLG format is needed which I believe I have by means of firmware update 6.2671 

https://www.sony.co.uk/electronics/support/downloads/00014882

Does anyone know if this model will support 4k Iplayer in the future?