diff --git a/phpBB/phpbb/db/doctrine/connection_parameter_factory.php b/phpBB/phpbb/db/doctrine/connection_parameter_factory.php
index bf0a18f5e8..4899f916f4 100644
--- a/phpBB/phpbb/db/doctrine/connection_parameter_factory.php
+++ b/phpBB/phpbb/db/doctrine/connection_parameter_factory.php
@@ -25,7 +25,7 @@ class connection_parameter_factory
 	 * Returns configuration options for Doctrine DBAL.
 	 *
 	 * @param string		$driver		Driver name.
-	 * @param string		$host		Hostname.
+	 * @param string|null	$host		Hostname.
 	 * @param string|null	$user		Username.
 	 * @param string|null	$password	Password.
 	 * @param string|null	$name		Database name.
@@ -37,7 +37,7 @@ class connection_parameter_factory
 	 */
 	public static function get_configuration(
 		string $driver,
-		string $host,
+		?string $host = null,
 		?string $user = null,
 		?string $password = null,
 		?string $name = null,
@@ -61,7 +61,7 @@ class connection_parameter_factory
 	 * Build Doctrine configuration array.
 	 *
 	 * @param array			$params		Parameter array.
-	 * @param string		$host		Database hostname.
+	 * @param string|null	$host		Database hostname.
 	 * @param string|null	$user		Username.
 	 * @param string|null	$password	Password.
 	 * @param string|null	$name		Database name.
@@ -73,7 +73,7 @@ class connection_parameter_factory
 	 */
 	private static function build_connection_parameters(
 		array $params,
-		string $host,
+		?string $host = null,
 		?string $user = null,
 		?string $password = null,
 		?string $name = null,
@@ -86,7 +86,7 @@ class connection_parameter_factory
 			);
 		}
 
-		if (empty($host) || empty($user) || empty($name))
+		if (empty($user) || empty($name))
 		{
 			throw new InvalidArgumentException('Required database parameter is not set.');
 		}