The Multi-Version Cluster mechanism lets you synchronize connections between cluster members that run different versions. This lets you upgrade to a newer version without a loss in connectivity and lets you test the new version on some of the cluster members before you decide to upgrade the rest of the cluster members. Acronym: MVC. (MVC) mechanism synchronizes connections between Cluster Two or more Security Gateways that work together in a redundant configuration - High Availability, or Load Sharing. Members that run different versions.