Access this global feature at Launchpad > Admin > Features > Global Features. Search for maintenance.
Maintenance mode allows the system to be locked down to specific users when performing system maintenance, such as upgrades or an import of a configuration package. Users not added to the access list will be shown a system maintenance screen with a configurable message.
Enabling, disabling or re-configuring maintenance mode requires a system-wide application restart, which may take several minutes.
Enabling maintenance mode will prevent users not listed in the Allowed users section from accessing the system. The system shows other users an information page with the given message.
Enabling maintenance mode sends a notification to all users of upcoming system maintenance/downtime.
