Odoo.sh, the hosting service from Odoo, primarily supports the three most recent versions of Odoo. This means that if you are using an older version, you will need to upgrade to a more recent version in order to use the hosting service.

However, if you are unable to upgrade to a more recent version for any reason, you can also use other hosting providers which support older version of Odoo.

It's important to note that, upgrading your version of Odoo can be a complex process, and it's recommended to have a good understanding of your current system and any customizations you've made before attempting it. You may want to consult the Odoo documentation and seek professional help if needed.