At this point, you can’t throw a rock without hitting an HDR-capable 4K TV, at least if you’re throwing rocks at an electronics store. Why do you do this? Stop it, you’re going to break something. Either way, if your TV has both 4K resolution and HDR capability, now you can use HBO Max to the fullest on your Chromecast.
HBO made the announcement with version 18.104.22.168 of its Android application, deployment now. This increases the resolution and dynamic range of Android phones, TVs, and set-top boxes that support it. “Select Titles” also supports Dolby Atmos.
This is all in preparation for HBO Max’s very first piece of 4K content, the hotly-trending streaming release of Wonder Woman 1984 the day of Christmas. At the time of writing, none of the service’s many catalogs are available in 4K, but the new Warner Bros. movies in 2021 will all land in a higher resolution, with “even more 4K UHD titles”. Hopefully this will include some of the older HBO series as well.
The new upgrade applies to the new Chromecast with Google TV (AKA a redesigned version of Android TV), the older Chromecast Ultra, NVIDIA’s various SHIELDs, and at least some of the TVs that manufacturers have preloaded with the Android TV operating system (mostly Sony). It may take a day or two for the update to spread widely.