You can find Frozen in 4K through several physical and digital formats: Frozen 4K Blu-ray Review - AVForums
Viewers can see improved textural niceties, such as the faint freckles on Anna’s cheeks, the dense fur on Sven, and the intricate icy blue accents on Elsa’s gown.
Unlike the standard Blu-ray which used a slightly cropped 2.24:1 frame, the 4K disc restores the film's original 2.39:1 theatrical aspect ratio , showing more information on the sides of the screen. Immersive Audio: Dolby Atmos