How do I stop the reminder for me to update?

[Promidi]

you could try blocking it in a firewall, unless you need continual web access

I have done this also for Designer Pro 16.2 and it worked there as well.

I am just hoping that Designer Pro does not need not phone home on a monthly basis in order to validate the licence.

[handrawn]

it will need to verify sooner or later I think, but you should be able to let it through and then block it again when it does