Odoo 11 custom Errorpage when updating system
I am new to Odoo and supported by a local company. They had set up Odoo 11 community. Once in a week they are doing backups and service on the system. During that time the system is not available and an ugly 503 Error is displayed.
I asked them to change this and to display a custom page indicating that the site is under maintenance. They suggested to install another Odoo instance with the website module and switch to that Odoo system during that time.
I am not a professional system administrator, so I would like to know if this is the only way to do maintenance work on the system. As far as I know, Odoo usually runs behind a webserver and it must not be too complicated to display a simple index.html site during the maintenance work or do I miss something ?