Just posting this in case someone else has the same issue. Overall everything went smoothly with the upgrade. Thanks Josh (and anybody else involved)!
However, with the assignment of a dedicated (not SLAAC) IPv6 address for the last 2 upgrades I’ve had to manually edit the nsd.conf file by including my server’s dedicated IPV6 address. The line I add just below the IPV4 server address is:
“ip-address: XXXX:XXXX:XXXX:0187::1”
Once I restart, the warning that my IPV6 service being not available on port 53 disappears. All is green.
Can you check the content of /etc/mailinabox.conf? There’s a variable there called PRIVATE_IPV6 which should contain the IPV6 address. If this is filled, you should bot have to add it manually.
I’d have to look up how this is normally filled, but if you put your IPv6 there (PRIVATE_IPV6=XXXX:XXXX:XXXX:0187::1) it will be used where needed (this also configures postfix to listen on that ipv6 address).
All is green on the checks and the server is running fine. Thanks for your feedback but I’m just going to leave as is for now. I have an upgrade note to make the change.
Different question though - am I misconfigured if my public and private IPV6 address are the same? I am not a network pro, less so with IPV6.