diff --git a/phpBB/phpbb/attachment/upload.php b/phpBB/phpbb/attachment/upload.php
index 2cdf61e511..dccd74dbc3 100644
--- a/phpBB/phpbb/attachment/upload.php
+++ b/phpBB/phpbb/attachment/upload.php
@@ -46,6 +46,9 @@ class upload
 	/** @var dispatcher */
 	protected $phpbb_dispatcher;
 
+	/** @var string */
+	protected $phpbb_root_path;
+
 	/** @var plupload Plupload */
 	protected $plupload;
 
diff --git a/phpBB/phpbb/config/config.php b/phpBB/phpbb/config/config.php
index a63890caf7..92d6857c32 100644
--- a/phpBB/phpbb/config/config.php
+++ b/phpBB/phpbb/config/config.php
@@ -50,6 +50,7 @@ class config implements \ArrayAccess, \IteratorAggregate, \Countable
 	* @param  string $key The configuration option's name.
 	* @return bool        Whether the configuration option exists.
 	*/
+	#[\ReturnTypeWillChange]
 	public function offsetExists($key)
 	{
 		return isset($this->config[$key]);
@@ -61,6 +62,7 @@ class config implements \ArrayAccess, \IteratorAggregate, \Countable
 	* @param  string $key The configuration option's name.
 	* @return int|string      The configuration value
 	*/
+	#[\ReturnTypeWillChange]
 	public function offsetGet($key)
 	{
 		return (isset($this->config[$key])) ? $this->config[$key] : '';
@@ -75,6 +77,7 @@ class config implements \ArrayAccess, \IteratorAggregate, \Countable
 	* @param string $key   The configuration option's name.
 	* @param string $value The temporary value.
 	*/
+	#[\ReturnTypeWillChange]
 	public function offsetSet($key, $value)
 	{
 		$this->config[$key] = $value;
@@ -85,6 +88,7 @@ class config implements \ArrayAccess, \IteratorAggregate, \Countable
 	*
 	* @param string $key The configuration option's name.
 	*/
+	#[\ReturnTypeWillChange]
 	public function offsetUnset($key)
 	{
 		trigger_error('Config values have to be deleted explicitly with the \phpbb\config\config::delete($key) method.', E_USER_ERROR);
diff --git a/phpBB/phpbb/datetime.php b/phpBB/phpbb/datetime.php
index e661a779db..7b9f9c83ac 100644
--- a/phpBB/phpbb/datetime.php
+++ b/phpBB/phpbb/datetime.php
@@ -57,6 +57,7 @@ class datetime extends \DateTime
 	* @param boolean $force_absolute Force output of a non relative date
 	* @return string Formatted date time
 	*/
+	#[\ReturnTypeWillChange]
 	public function format($format = '', $force_absolute = false)
 	{
 		$format		= $format ? $format : $this->user->date_format;
diff --git a/phpBB/phpbb/event/data.php b/phpBB/phpbb/event/data.php
index 6095903067..963da092aa 100644
--- a/phpBB/phpbb/event/data.php
+++ b/phpBB/phpbb/event/data.php
@@ -44,21 +44,25 @@ class data extends Event implements \ArrayAccess
 		return array_intersect_key($this->data, array_flip($keys));
 	}
 
+	#[\ReturnTypeWillChange]
 	public function offsetExists($offset)
 	{
 		return isset($this->data[$offset]);
 	}
 
+	#[\ReturnTypeWillChange]
 	public function offsetGet($offset)
 	{
 		return isset($this->data[$offset]) ? $this->data[$offset] : null;
 	}
 
+	#[\ReturnTypeWillChange]
 	public function offsetSet($offset, $value)
 	{
 		$this->data[$offset] = $value;
 	}
 
+	#[\ReturnTypeWillChange]
 	public function offsetUnset($offset)
 	{
 		unset($this->data[$offset]);