Hi everyone

I have a question about the data protection/data security of Odoo in the context of an upgrade. 

Is it effectively the case that upgrades of Odoo databases must always be performed via https://upgrade.odoo.com/upgrade? Or is there a way to handle an upgrade independently of the Odoo Upgrade Service (e.g. for a sensitive, on-premise environments)?

What exactly does the Odoo Upgrade Service do and where is an alternative, independent way documented?

Thanks in advance for your replys!

Benno