For an upgrade, your config file is located in /includes/config.inc.php
For a fresh install, there will be no config file, as the installer is the tool which requests basic configuration information from you, to generate that /includes/config.inc.php file.
Accessing /install/index.php directly will determine if you are doing an install or upgrade.
Last edited by isaac; 08/09/2019 1:57 PM. Reason: a word