Failover groups that use more than one version of Sun Ray Software will be unable to use all the features provided in the latest releases. But, a failover group can be a heterogeneous group of Sun Ray servers running different versions of Sun Ray Software.
When multiple versions of Sun Ray Software are used in a failover group, the primary server should run the oldest of the versions in use. Otherwise, the presence of a newer feature on the primary server might prevent proper replication of the Sun Ray data store to secondary servers that are running older versions.