Almost a year ago, HDR support came to Google Play Movies & TV through Google's 4K streaming dongle, the Chromecast Ultra. Now, compatible Sony smart TVs and the best Android decoder in the game, Nvidia Shield TV, also receive support for HDR content from Google Play, but only if they are broadcast from another device.
Of course, you can not watch HDR movies on any old screen. You will need a compatible TV, not all Sony are HDR enabled, as well as an Internet connection that can manage a 4K video stream. The 4K / HDR support page recommends a connection that can maintain a stable download speed of 15 megabits per second or more (Google has a quick and easy test that you can access by searching for "Internet speed test").
While it's a bit When you see that you can not watch only HDR movies in the Play Movies & TV application that is already on your TV, the extra step of transmitting them does not take that long. Something is better than nothing.
You can search for a list of available HDR movies on Google Play Movies & TV here.