Wireless Access

Hi All,

Today, we upgraded from 8.10.0.15 to 8.10.0.19. No issues on the 2 mobility conductors nor on 8 out of the 9 controllers. For one of the controllers, there was a message that said error in upgrade. Since the scheduled maintenance time was running out, I shutdown the ports from the switch for the controller that was not able to upgrade. This controller is 1 of 3 in a cluster and I wanted the APs to be upgraded in time. 

My question is, what is the best way to upgrade/fix the remaining controller? Correct me if I'm wrong but if I bring the controller back online, some of the APs will try to terminate to that controller which means it'll try to downgrade back to 8.10.0.15.

Thank you ahead of time to anyone who can help.

Disregard, this is all set. Controller was removed from the cluster, upgraded via CLI, and then re-added into cluster. 

If you had started the controller with the down version still installed, what should have happened is the cluster refusing the down version controller from joining the cluster and the IP address wouldn't have been added to the node-list for the APs to consider that controller as an option.