ISO7740: NC pin connection

Part Number: ISO7740

Hello team,

My customer is drawing circuit with our ISO7740 for their cobot pjt, and was wondering how to connect the NC pins. It was not quite clear on the datasheet, could you please share your feedback on below?

  1. IC's NC pin: Should leave floating or connect to GND?
  2. Unused pin: Should leave floating or connect to GND?

Thank you.