The following set of tasks are the recommended order for upgrading your environment.
To avoid having endpoints lose connection to PolicyServer, make sure to upgrade PolicyServer before upgrading the agents. The keys to access data encrypted on those endpoints may become inaccessible if you upgrade in the wrong order.
If an agent is unable to connect to PolicyServer after the upgrade, manually run the upgrade installer on the endpoint.
See System Requirements.
See the OfficeScan Plug-in Online Help.