The industry association VESA has published a new variant of the DisplayHDR Standard, the "DisplayHDR True Black", which is specially optimized for displays using light emitting technologies such as OLED and Micro LED.
DisplayHDR True Black provides up to 100x lower black levels (i.e. true black), a wider dynamic range and 4x better response time from black to white compared to VESA's DisplayHDR 1000 standard. Also new is the DisplayHDR 500 standard, which is specifically designed for ultra-thin notebooks and defines local dimming as well as high contrast and color quality at a relatively low price and thermal output.
Here you can read the exact specifications of the new standards DisplayHDR 400 True Black and DisplayHDR 500 True Black, which stand out from their respective counterparts DisplayHDR 400 and DisplayHDR 500 primarily due to their better black value and better response time.