We use a staging page for testing the new version. We copied a running instance of 1.16.3 to the staging folder and updated it to 1.17.0.
This staging page connects to the same database and tables from version 1.16.3.
While the 1.16.3 can be accessed normally, the 1.17.0 is showing up in “offline mode”. Even with disabled cache and cookies and all plugins removed. Loggin into the SCP-Interface with an local administrative account, then also “System offline” is displayed after “login” and the login-page is showing up again.