---
title: "Breaking: #75454 - LocalConfiguration DB config structure has changed"
manual: "TYPO3 Core Changelog"
version: "main"
permalink: "https://docs.typo3.org/permalink/changelog:breaking-75454"
source: "Changelog/8.1/Breaking-75454-LocalConfigurationDBConfigStructureHasChanged.rst"
modified: "2026-09-15T10:46:36+00:00"
---

# Breaking: #75454 - LocalConfiguration DB config structure has changed

See [forge#75454](https://forge.typo3.org/issues/75454)

## Description

To provide support for multiple database connections and remapping tables to different
database systems within the TYPO3 Core the configuration format for database connections
in `LocalConfiguration.php` / `$GLOBALS['TYPO3_CONF_VARS']['DB']` has changed.

The new configuration array structure:

```php
'DB' => [
    'Connections' => [
        'Default' => [
            'driver' => 'mysqli',
            'dbname' => 'typo3_database',
            'password' => 'typo3',
            'host' => '127.0.0.1',
            'port' => 3306,
            'user' => 'typo3',
            'unix_socket' => '',
            'charset' => 'utf-8',
        ],
    ],
],
```

Be aware that besides the deeper nesting below 'Connections/Default' some of the configuration
keys have been renamed. It is required to provide the new configuration key `driver` with a
value of `mysqli` explicitly.

The following table lists the changed configuration keys and the appropriate values if these
have changed.

| Old name | New name |
| --- | --- |
| DB/username | DB/Connections/Default/user |
| DB/password | DB/Connections/Default/password |
| DB/host | DB/Connections/Default/host |
| DB/port | DB/Connections/Default/port |
| DB/socket | DB/Connections/Default/unix_socket |
| DB/database | DB/Connections/Default/dbname |
| SYS/setDBinit | DB/Connections/Default/initCommands |
| SYS/no_pconnect | DB/Connections/Default/persistentConnection |
| SYS/dbClientCompress | DB/Connections/Default/driverOptions Valid values for MySQLi connections: 0  compression disabled 32 compression enabled |

## Impact

Connections to the database will fail with an exception until the configuration has been migrated
to the new structure.

## Affected Installations

All Installations

## Migration

The Install Tool will migrate the configuration information for the default connection to the new
format. Installations overriding the database configuration using `AdditionalConfiguration.php`
or other means need to ensure the new format is being used.