SEK-4500U has been replaced by a so called BIG FW update for 2016, containing Tizen 2.0, possibly 3.0. No other info has been forth coming. (Amazon and Netflix HDR availabilty?)
Currently, the FW is classified as Vaporware.
Promised for April 2016, then June, and now supposedly September.
Time will tell if it retains it's Vaporware status, or actually bears fruit?
A LOT of people are waiting!