The procedure to upgrade a Redundancy Group containing two SBCs in a 1:1 HA formation is essentially the same as the process to upgrade up to five SBC instances in an N:1 Redundancy Group, except that you only need to upgrade two nodes. To upgrade an SBC 1:1 HA deployment, refer to the procedure Upgrading SBCs in an N:1 Redundancy Group and complete the steps to upgrade the first two nodes, beginning with the standby SBC.