While several companies jostled to be the first to release a 4K Blu-ray player last year LG uncharacteristically waited a full 12 months to announce its own: the UP970. There are advantages to this approach: Firstly, there are about 100 4K discs available for purchase right now as opposed to a handful back then. Secondly, the standards involved are starting to sift themselves out so that potential buyers now know what they'll need their player to support. Namely things like HDR10 and Dolby Vision.
The LG UP970 will support Dolby Vision with an update coming a few months after its March release, and this is designed to coincide with the release of Dolby Vision titles.
Otherwise this is a UHD Blu-ray player with support for HDR (10) and discs with a resolution of 3,840 by 2,160 pixels.
https://www.cnet.com/products/lg-up970/preview/