If you have an earlier version of Fusion, you can upgrade by using the DVD in the software packaging for the current version.
If you are upgrading Fusion, you must uninstall the version that is installed on your Mac. Installing, upgrading, and uninstalling of Fusion does not modify existing virtual machines.
When the upgrade is finished, you must upgrade VMware Tools in every virtual machine. A VMware Tools upgrade requires that you restart the virtual machine. See Installing or Upgrading VMware Tools.