Blu-ray 4K is officially called Ultra HD Blu-ray – major new details on the spec extension from the BDA
Amazon.com: Upgrade - 4K Ultra HD + Blu-ray [4K UHD] : Logan Marshall-Green, Betty Gabriel, Harrison Gilbertson, Leigh Whannell, Jason Blum, Kylie Du Fresne, Brian Kavanaugh-Jones, Leigh Whannell: Movies & TV