Is there any way to schedule an OS update by using Watchguard System Manager and without the use of a management/dimension server?
Unfortunately, there's no way to schedule an upgrade without either a Management server, or Dimension Command.
If you open the firewall's WatchGuard/WatchGuard WebUI rules to the external IPs you'll be at, you can initiate the upgrade remotely, however.
WatchGuard Customer Support
Yes we currently have the rules to allow management from our IP, it was more to be able to schedule the update out of hours and unattended. Thanks for the info James.