New patent application shows a possible Canon FF mirrorless mount

Fig.1 is the figure which looked at the mount part of the camera of the first embodiment concerning the present invention from the lens side. As for camera body side mount and 1A, in the figure, 1 is [ a mount lock pin and 3A of the camera body side attachment surface, 1C1, 1C2, and 1C3 ] the camera body side electric connection terminals a camera-body-side-mount nail and 2, respectively. 

Thew new Japanese patent application number 2018-084713 describes what could be the new Canon Full Frame mirrorless mount. Sadly Canon did not share info about the exact mount size. All Canon writes is that it has a “high-speed electrical connection”.

via Hi Lows Note