Plesk modules is the mechanism for enhancing the product functionality without the need to release a new version. The mechanism itself is similar to the Application Vault. The only difference is that an addon in case of Plesk modules is installed in the control panel, but not on a virtual host. The main property of this approach is independence of modules from the product itself. It means that any actions in the main product (for example, creation, renaming, or removal of objects) do not effect modules in any way. Moreover, it allows for updating modules and Plesk independently.