diff --git a/src/Settings.php b/src/Settings.php
index 0d0089a..0f30031 100644
--- a/src/Settings.php
+++ b/src/Settings.php
@@ -270,7 +270,7 @@ class Settings implements \Iterator, \Countable
 	 * Rewind the Iterator to the first element
 	 * @link https://www.php.net/iterator.rewind
 	 */
-	public function rewind()
+	public function rewind(): void
 	{
 		reset( $this->settings);
 	}
@@ -279,7 +279,7 @@ class Settings implements \Iterator, \Countable
 	 * Return the current element
 	 * @link https://www.php.net/iterator.current
 	 */
-	public function current()
+	public function current(): mixed
 	{
 		return current( $this->settings );
 	}
@@ -288,7 +288,7 @@ class Settings implements \Iterator, \Countable
 	 * Return the key of the current element
 	 * @link https://www.php.net/iterator.key
 	 */
-	public function key()
+	public function key(): mixed
 	{
 		return key( $this->settings );
 	}
@@ -297,16 +297,16 @@ class Settings implements \Iterator, \Countable
 	 * Move forward to next element
 	 * @link https://www.php.net/iterator.next
 	 */
-	public function next()
+	public function next(): void
 	{
-		return next( $this->settings );
+		next( $this->settings );
 	}
 
 	/**
 	 * Checks if current position is valid
 	 * @link https://www.php.net/iterator.valid
 	 */
-	public function valid()
+	public function valid(): bool
 	{
 		$key = key( $this->settings );
 		return ($key !== null && $key !== false);