Back up your data.
Use the Windows Control Panel to uninstall your client application, the PlateSpin Migrate Client.
On your server host, start the PlateSpinMigrateSetup-12.2.1.X.exe installation program.
Click Install Server and follow the on-screen instructions. When you are prompted to specify a database instance, point the installation program to your existing database instance.
Install the current version of the PlateSpin Migrate Client.
(Optional) After the upgrade, you should upload again any custom Linux blkwatch drivers you need for future migrations. See KB Article 7005873.
See also Backing Up Your Custom Linux blkwatch Drivers Before Upgrade.