---
title: "Configuration files"
manual: "TYPO3 Explained"
version: "11.5"
permalink: "https://docs.typo3.org/permalink/t3coreapi:configuration-files@11.5"
source: "Configuration/ConfigurationFiles.rst"
rendered: "2026-10-21T15:30:00+00:00"
---

> [!WARNING]
> **Attention**
>
> TYPO3 v11 has reached end-of-life as of October 31th 2024 and
> is no longer being maintained. Use the version switcher on the top
> left of this page to select documentation for a supported version of TYPO3.
>
> Need more time before upgrading?
> You can purchase Extended Long Term Support (ELTS) for TYPO3 v11 here:
> [TYPO3 ELTS](https://typo3.com/services/extended-support-elts).

# Configuration files {#configuration-files}

The configuration files `LocalConfiguration.php` and
`AdditionalConfiguration.php` are located in the directory
[public/typo3conf/](https://docs.typo3.org/permalink/t3coreapi:directory-public-typo3conf@11.5) 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.