If you want to install a new version of Encryptability on a computer that already has an older version of Encryptability installed, you do not need to uninstall the old version first. What you need to do, though, is stop all Virtual Encrypted Disks currently active on the computer before starting the upgrade. (If you forget to stop such a disk, the installation utility of Encryptability should remind you about it.)
After you've stopped all Virtual Encrypted Disks, run the installation file with the new version of Encryptability, and it should replace the old version with the new one (that is, upgrade your version of Encryptability).