High resolution HDR pictures are not displayed.

The following are required to watch high resolution HDR pictures such as 4K (50p/60p)*.

Connect the 4K (50p/60p)* playable device.
Use a Premium High Speed HDMI Cable(s) that supports 18 Gbps.
Set [HDMI signal format] to [Enhanced format] by selecting [Settings] — [BRAVIA Settings] — [External inputs] — [HDMI signal format] — the HDMI terminal you want to set.
Check whether the connected device has the latest settings or firmware.