The V3 supports a wider range of inputs, including Sega Saturn , SNK Neo Geo AES , and even modern PS4/Xbox One controllers via USB.
New API commands allow for better handling of extracted audio. This mitigates audio lag or drops when audio formats change suddenly. How to Perform the Update cbox v3 update
Since this is primarily a hardware revision, "updating" usually means purchasing the latest V3.0 board or upgrading specific components like the Unibios (often v3.3 or higher). The V3 supports a wider range of inputs,