How do I recover an old previous file version?

Previous versions of files can be recovered in the web UI and in the mobile application.

In both cases, select the file in question, then select the "Versions" option. You will be able to see the previous versions of the file (along with the size, latest action on file, and date it was changed), and select to revert back to the version you want.

Please note that the administrator can configure the retention policy (number of versions to be retained, and retention duration), so you will only be able to revert back to a version that is still known to Syncplicity.