diff --git a/PHPExcel/PHPExcel/WorksheetIterator.php b/PHPExcel/PHPExcel/WorksheetIterator.php
index cb1b281..789fb24 100755
--- a/PHPExcel/PHPExcel/WorksheetIterator.php
+++ b/PHPExcel/PHPExcel/WorksheetIterator.php
@@ -60,9 +60,10 @@ class PHPExcel_WorksheetIterator implements Iterator
         unset($this->subject);
     }
 
-    /**
+   /**
      * Rewind iterator
      */
+    #[\ReturnTypeWillChange]
     public function rewind()
     {
         $this->position = 0;
@@ -73,6 +74,7 @@ class PHPExcel_WorksheetIterator implements Iterator
      *
      * @return PHPExcel_Worksheet
      */
+    #[\ReturnTypeWillChange]
     public function current()
     {
         return $this->subject->getSheet($this->position);
@@ -83,6 +85,7 @@ class PHPExcel_WorksheetIterator implements Iterator
      *
      * @return int
      */
+    #[\ReturnTypeWillChange]
     public function key()
     {
         return $this->position;
@@ -91,6 +94,7 @@ class PHPExcel_WorksheetIterator implements Iterator
     /**
      * Next value
      */
+    #[\ReturnTypeWillChange]
     public function next()
     {
         ++$this->position;
@@ -101,6 +105,7 @@ class PHPExcel_WorksheetIterator implements Iterator
      *
      * @return boolean
      */
+    #[\ReturnTypeWillChange]
     public function valid()
     {
         return $this->position < $this->subject->getSheetCount();