For information about supported upgrade paths for FortiClient, see the FortiClient and FortiClient EMS Upgrade Paths.
An administrator will control FortiClient upgrades for you. See EMS and automatic upgrade of FortiClient.
When an administrator deploys a FortiClient upgrade from EMS to endpoints running a Windows operating system, an Upgrade Schedule dialog displays in advance on the endpoint to let endpoint users schedule the upgrade and mandatory endpoint reboot. If no FortiClient is installed on the endpoint, no reboot is required for the installation, and no Upgrade Schedule dialog displays. The endpoint user can postpone the reboot for a maximum of 24 hours. Before the mandatory reboot occurs, a FortiClient dialog displays with a 15 minute warning.