Sony patented a new mount design that condenses some of the lens handshake functions to reduce the mounts pint count. A normal E-mount pin count is 10-pins, but Sony’s new design is 8-pins. This could be a technology that Sony will use later in a medium format camera, but Fujifilm added pins for theirs for the ability to adapt lenses. This reduced pin count could also add flexibility going forward Since Sony could have more pins to work with if they reduce the native pin count of their lenses on a future system.