When I upgraded from Cells v1.6.1 to v2.0.1 I received the following message
Binary package has been successfully verified, you can now restart Cells.
WARNING: you are using the reserved port 443.
You must execute following command to authorize the new binary to use this port before restarting your instance:
$ sudo setcap ‘cap_net_bind_service=+ep’ <path to your binary>
The issue here is that “<path to your binary>” is very unhelpful. I figured out that it meants the “cells” executable, but even that’s not clear. It would be very helpful to explicitly include the path in this notification.