Upgrade Process?

I'm currently running v5.9.3 and would like to upgrade to the latest version 5.21.
Do I need to uninstall the old one or just install the new one over it?

Nevermind. I downloaded the new version, backed up my install directory, ran the installer and the first option was to do a full upgrade. So far, so good.

See https://winscp.net/eng/docs/installation#upgrade