Hi,

On Odoo Online (SaaS), the best way to create a test environment is to duplicate the production database from the portal. Since this copy includes live data, you can then sanitize it by deleting records or instead create a brand-new blank database and import only configuration. When Odoo 19 is released, Odoo will provide a test upgrade database so you can validate before going live. Keep in mind that on SaaS you cannot directly publish test changes to production, instead, validated configurations or workflows must be reapplied manually or imported. This ensures a safe test setup without handling sensitive client data.

* https://www.odoo.com/documentation/19.0/administration/odoo_online.html

* https://www.cybrosys.com/blog/odoo-online

Hope it helps