The Primary and Secondary nodes in a cluster must be running the same firmware version on the same hardware version (V1 or E1).
Your CC-SG network must be in IP Failover mode to be used for clustering. Clustering will not work with an IP Isolation mode configuration. See About Network Setup.
Clusters are not supported on IPv6.
Date, time, and time zone settings are not replicated from the Primary node to the Secondary node. You must configure these settings in each CC-SG before you create the cluster.