This feature is available with artica version 1.4.041815
If you are under this release you need to upgrade your Artica version.
If this version is not released use the How to upgrade Artica to a nightly build ?
It allows you to shutdown the computer when disconnecting trough the Artica Interface.
- Click on "System Config." on the front-end web page.
- Choose "Index Page"
- Check "Enable Shutdown button when disconnecting"

When disconnecting a new button is displayed and allow you to turn off the computer





