diff --git a/php/src/Google/Protobuf/Internal/MapField.php b/php/src/Google/Protobuf/Internal/MapField.php
index 86463a9a47..d44377a179 100644
--- a/php/src/Google/Protobuf/Internal/MapField.php
+++ b/php/src/Google/Protobuf/Internal/MapField.php
@@ -135,6 +135,7 @@ class MapField implements \ArrayAccess, \IteratorAggregate, \Countable
      * @return object The stored element at given key.
      * @throws \ErrorException Invalid type for index.
      * @throws \ErrorException Non-existing index.
+     * @todo need to add return type mixed (require update php version to 8.0)
      */
     #[\ReturnTypeWillChange]
     public function offsetGet($key)
@@ -153,6 +154,7 @@ class MapField implements \ArrayAccess, \IteratorAggregate, \Countable
      * @throws \ErrorException Invalid type for key.
      * @throws \ErrorException Invalid type for value.
      * @throws \ErrorException Non-existing key.
+     * @todo need to add return type void (require update php version to 7.1)
      */
     #[\ReturnTypeWillChange]
     public function offsetSet($key, $value)
@@ -212,6 +214,7 @@ class MapField implements \ArrayAccess, \IteratorAggregate, \Countable
      * @param object $key The key of the element to be removed.
      * @return void
      * @throws \ErrorException Invalid type for key.
+     * @todo need to add return type void (require update php version to 7.1)
      */
     #[\ReturnTypeWillChange]
     public function offsetUnset($key)
diff --git a/php/src/Google/Protobuf/Internal/MapFieldIter.php b/php/src/Google/Protobuf/Internal/MapFieldIter.php
index a3c834bd2c..2ff6b44ae3 100644
--- a/php/src/Google/Protobuf/Internal/MapFieldIter.php
+++ b/php/src/Google/Protobuf/Internal/MapFieldIter.php
@@ -67,6 +67,7 @@ class MapFieldIter implements \Iterator
      * Reset the status of the iterator
      *
      * @return void
+     * @todo need to add return type void (require update php version to 7.1)
      */
     #[\ReturnTypeWillChange]
     public function rewind()
@@ -78,6 +79,7 @@ class MapFieldIter implements \Iterator
      * Return the element at the current position.
      *
      * @return object The element at the current position.
+     * @todo need to add return type mixed (require update php version to 8.0)
      */
     #[\ReturnTypeWillChange]
     public function current()
@@ -89,6 +91,7 @@ class MapFieldIter implements \Iterator
      * Return the current key.
      *
      * @return object The current key.
+     * @todo need to add return type mixed (require update php version to 8.0)
      */
     #[\ReturnTypeWillChange]
     public function key()
@@ -119,6 +122,7 @@ class MapFieldIter implements \Iterator
      * Move to the next position.
      *
      * @return void
+     * @todo need to add return type void (require update php version to 7.1)
      */
     #[\ReturnTypeWillChange]
     public function next()
diff --git a/php/src/Google/Protobuf/Internal/RepeatedField.php b/php/src/Google/Protobuf/Internal/RepeatedField.php
index 704123ad15..cfe5140d77 100644
--- a/php/src/Google/Protobuf/Internal/RepeatedField.php
+++ b/php/src/Google/Protobuf/Internal/RepeatedField.php
@@ -121,6 +121,7 @@ class RepeatedField implements \ArrayAccess, \IteratorAggregate, \Countable
      * @return object The stored element at given index.
      * @throws \ErrorException Invalid type for index.
      * @throws \ErrorException Non-existing index.
+     * @todo need to add return type mixed (require update php version to 8.0)
      */
     #[\ReturnTypeWillChange]
     public function offsetGet($offset)
@@ -139,6 +140,7 @@ class RepeatedField implements \ArrayAccess, \IteratorAggregate, \Countable
      * @throws \ErrorException Invalid type for index.
      * @throws \ErrorException Non-existing index.
      * @throws \ErrorException Incorrect type of the element.
+     * @todo need to add return type void (require update php version to 7.1)
      */
     #[\ReturnTypeWillChange]
     public function offsetSet($offset, $value)
@@ -211,6 +213,7 @@ class RepeatedField implements \ArrayAccess, \IteratorAggregate, \Countable
      * @throws \ErrorException Invalid type for index.
      * @throws \ErrorException The element to be removed is not at the end of the
      * RepeatedField.
+     * @todo need to add return type void (require update php version to 7.1)
      */
     #[\ReturnTypeWillChange]
     public function offsetUnset($offset)
diff --git a/php/src/Google/Protobuf/Internal/RepeatedFieldIter.php b/php/src/Google/Protobuf/Internal/RepeatedFieldIter.php
index 3c85869989..ec99b64ae7 100644
--- a/php/src/Google/Protobuf/Internal/RepeatedFieldIter.php
+++ b/php/src/Google/Protobuf/Internal/RepeatedFieldIter.php
@@ -70,6 +70,7 @@ class RepeatedFieldIter implements \Iterator
      * Reset the status of the iterator
      *
      * @return void
+     * @todo need to add return type void (require update php version to 7.1)
      */
     #[\ReturnTypeWillChange]
     public function rewind()
@@ -81,6 +82,7 @@ class RepeatedFieldIter implements \Iterator
      * Return the element at the current position.
      *
      * @return object The element at the current position.
+     * @todo need to add return type mixed (require update php version to 8.0)
      */
     #[\ReturnTypeWillChange]
     public function current()
@@ -92,6 +94,7 @@ class RepeatedFieldIter implements \Iterator
      * Return the current position.
      *
      * @return integer The current position.
+     * @todo need to add return type mixed (require update php version to 8.0)
      */
     #[\ReturnTypeWillChange]
     public function key()
@@ -103,6 +106,7 @@ class RepeatedFieldIter implements \Iterator
      * Move to the next position.
      *
      * @return void
+     * @todo need to add return type void (require update php version to 7.1)
      */
     #[\ReturnTypeWillChange]
     public function next()