When you add or change something on Kooboo, Kooboo automatically does a version control on the following items.
All content except sub content
Content template
Layout template
Text resource

To access the version history, right click on any item and select version

This opens the version control windows and lists the version history

You can select one item and click "Show Snapshot" button to see the detail content of that item or click "Revert To" to restore back to that earlier version. "Revert To" will create a new version based on an earlier version; All your editing history will still be kept.