diff --git a/phpBB/phpbb/install/module/install_finish/task/install_extensions.php b/phpBB/phpbb/install/module/install_finish/task/install_extensions.php
index 47ea156c66..c398323bc4 100644
--- a/phpBB/phpbb/install/module/install_finish/task/install_extensions.php
+++ b/phpBB/phpbb/install/module/install_finish/task/install_extensions.php
@@ -13,6 +13,7 @@
 
 namespace phpbb\install\module\install_finish\task;
 
+use phpbb\config\db;
 use phpbb\install\exception\resource_limit_reached_exception;
 
 /**
@@ -31,7 +32,7 @@ class install_extensions extends \phpbb\install\task_base
 	protected $iohandler;
 
 	/**
-	 * @var \phpbb\config\db
+	 * @var db
 	 */
 	protected $config;
 
@@ -74,7 +75,6 @@ class install_extensions extends \phpbb\install\task_base
 		$this->log				= $container->get('log');
 		$this->user				= $container->get('user');
 		$this->extension_manager = $container->get('ext.manager');
-		$this->config			= $container->get('config');
 		$this->db				= $container->get('dbal.conn');
 		$this->finder = new \Symfony\Component\Finder\Finder();
 		$this->finder->in($phpbb_root_path . 'ext/')
@@ -83,6 +83,19 @@ class install_extensions extends \phpbb\install\task_base
 			->files()
 			->name('composer.json');
 
+		/** @var \phpbb\cache\driver\driver_interface $cache */
+		$cache = $container->get('cache.driver');
+		$cache->destroy('config');
+
+		$this->config = new db(
+			$this->db,
+			$cache,
+			$container->get_parameter('tables.config')
+		);
+
+		global $config;
+		$config = $this->config;
+
 		// Make sure asset version exists in config. Otherwise we might try to
 		// insert the assets_version setting into the database and cause a
 		// duplicate entry error.
diff --git a/phpBB/phpbb/install/module/install_finish/task/notify_user.php b/phpBB/phpbb/install/module/install_finish/task/notify_user.php
index 292be57f5f..b045b708db 100644
--- a/phpBB/phpbb/install/module/install_finish/task/notify_user.php
+++ b/phpBB/phpbb/install/module/install_finish/task/notify_user.php
@@ -97,6 +97,9 @@ class notify_user extends \phpbb\install\task_base
 			$container->get_parameter('tables.config')
 		);
 
+		global $config;
+		$config = $this->config;
+
 		parent::__construct(true);
 	}
 
@@ -112,11 +115,6 @@ class notify_user extends \phpbb\install\task_base
 		{
 			include ($this->phpbb_root_path . 'includes/functions_messenger.' . $this->php_ext);
 
-			// functions_messenger.php uses config to determine language paths
-			// Remove when able
-			global $config;
-			$config = $this->config;
-
 			$messenger = new \messenger(false);
 			$messenger->template('installed', $this->install_config->get('user_language', 'en'));
 			$messenger->to($this->config['board_email'], $this->install_config->get('admin_name'));
diff --git a/phpBB/phpbb/session.php b/phpBB/phpbb/session.php
index 58d56ff3f3..b7bb364ec9 100644
--- a/phpBB/phpbb/session.php
+++ b/phpBB/phpbb/session.php
@@ -25,7 +25,6 @@ class session
 	var $forwarded_for = '';
 	var $host = '';
 	var $session_id = '';
-	public $id = ANONYMOUS;
 	var $ip = '';
 	var $load = 0;
 	var $time_now = 0;
@@ -363,8 +362,6 @@ class session
 			// Did the session exist in the DB?
 			if (isset($this->data['user_id']))
 			{
-				$this->id = (int) $this->data['user_id'];
-
 				// Validate IP length according to admin ... enforces an IP
 				// check on bots if admin requires this
 //				$quadcheck = ($config['ip_check_bot'] && $this->data['user_type'] & USER_BOT) ? 4 : $config['ip_check'];
@@ -650,7 +647,7 @@ class session
 		}
 
 		// Force user id to be integer...
-		$this->id = $this->data['user_id'] = (int) $this->data['user_id'];
+		$this->data['user_id'] = (int) $this->data['user_id'];
 
 		// At this stage we should have a filled data array, defined cookie u and k data.
 		// data array should contain recent session info if we're a real user and a recent
@@ -1667,4 +1664,14 @@ class session
 			}
 		}
 	}
+
+	/**
+	 * Get user ID
+	 *
+	 * @return int User ID
+	 */
+	public function id() : int
+	{
+		return isset($this->data['user_id']) ? (int) $this->data['user_id'] : ANONYMOUS;
+	}
 }
diff --git a/phpBB/phpbb/user.php b/phpBB/phpbb/user.php
index e02563a7cc..1288ddf524 100644
--- a/phpBB/phpbb/user.php
+++ b/phpBB/phpbb/user.php
@@ -641,7 +641,7 @@ class user extends \phpbb\session
 	 * Create a DateTimeZone object in the context of the current user
 	 *
 	 * @param string $user_timezone Time zone of the current user.
-	 * @return DateTimeZone DateTimeZone object linked to the current users locale
+	 * @return \DateTimeZone DateTimeZone object linked to the current users locale
 	 */
 	public function create_timezone($user_timezone = null)
 	{