Sametime Gateway 8.0.2 can be upgraded directly to release 8.5.2. But if you have an earlier release, you must perform an interim upgrade to release 8.0.2 before you can upgrade to Sametime Gateway 8.5.2. The install for the upgrade also upgrades WAS from version 6 to version 7. If your Sametime Gateway environment was clustered, then prior to the upgrade you will need to remove each node from the cluster; proceed with upgrading the cluster server and then add them back to the node. In Sametime 8.5.2, you can only have one secondary node.