Configuration files

The configuration files LocalConfiguration.php and AdditionalConfiguration.php are located in the directory public/typo3conf/ in Composer-based installations. In legacy installations they are located in typo3conf/.

The most important configuration file is LocalConfiguration.php. It contains local settings of the main global PHP array $GLOBALS['TYPO3_CONF_VARS'], crucial settings like database connect credentials are in here. The file is managed by the Admin Tools.

The settings in the LocalConfiguration.php can be overridden in the AdditionalConfiguration.php file, which is never touched by TYPO3 internal management tools. Be aware that having settings within AdditionalConfiguration.php may prevent the system from performing automatic upgrades and should be used with care and only if you know what you are doing.