1+1 High Availability clusters can provide continuous access to services during upgrades, when you upgrade one server at a time.
High Availability servers are upgraded as follows:
Enable Local High Availability State Lock on the Active server.
Upgrade the Standby server by performing the procedure to upgrade a simplex media server.
Disable the Local High Availability State Lock on the Active server and failover to the newly upgraded Standby server.
Enable Local High Availability State Lock on the newly Active server.
Upgrade the Standby server by performing the procedure to upgrade a simplex media server.
Disable the Local High Availability State Lock on the Active server.