I closed the browser window by accident while upgrading. I could not access admin.php, and on domain.com only a "this community is upgrading" message was visible. After ... # php library/XenForo/Install/run-upgrade.php the upgrade process went through with these messages The message on domain.com still was the same ("... is upgrading"). I could access admin.php and got a "please click here to upgrade" link. The upgrade then went fine. Maybe this thread may help others experiencing similar issues. Please note that I always have trouble with the CLI upgrade as I copy the xenforo files with a different linux file system owner than the one my webserver is using. This is not a problem of xenforo. Nevertheless, whoever experiences a similar situation, this might help.