This seems like quite an update to Blackmagic's handheld video camera. The new Pocket Cinema Camera 4K sports a vastly updated design, a new Four Thirds-size sensor, support for DCI 4K/60p video and the ability to connect and record directly to USB-C storage devices.
The changes put it in direct competition with the Panasonic GH5s announced earlier this year. Like that camera, the PCC4K has a multi-aspect-ratio, dual ISO sensor, though it has a native high sensitivity of ISO 25600; like the HD model, Blackmagic claims 13 stops of dynamic range. It also specs the the effective dimensions as the full 18.96mm by 10mm Four Thirds sensor dimensions, rather than the usual 4:3 17.3 by 13mm crop from which it gets its name.
The full sensor, though, is the same aspect ratio as DCI 4K, 17:9. (I think Panasonic starts with a slightly higher-resolution sensor and changes the crop to get the 17:9 aspect for its implementation. Blackmagic doesn't say what resolution its sensor is.) And it's bigger than the Super 16 sensor in the previous model, while making better use of the Micro Four Thirds platform.
Other notable updates include support for 10-bit ProRes and 12-bit raw recording, 3D LUTs and four built in microphones. The combination of the dual native ISO, improved capture bit depths and the LUTs should allow it to deliver HDR video.