diff --git a/BigQuery/src/QueryResults.php b/BigQuery/src/QueryResults.php
index f09db23e091c..0f37b3b6c295 100644
--- a/BigQuery/src/QueryResults.php
+++ b/BigQuery/src/QueryResults.php
@@ -352,6 +352,7 @@ public function job()
      *         query completion has been exceeded.
      * @throws GoogleException Thrown in the case of a malformed response.
      */
+    #[\ReturnTypeWillChange]
     public function getIterator()
     {
         return $this->rows();
diff --git a/Bigtable/src/ChunkFormatter.php b/Bigtable/src/ChunkFormatter.php
index db3b923eb650..adb31e7a536f 100644
--- a/Bigtable/src/ChunkFormatter.php
+++ b/Bigtable/src/ChunkFormatter.php
@@ -490,6 +490,7 @@ private function cellInProgress(CellChunk $chunk)
      * @return \Generator
      * @throws BigtableDataOperationException Thrown in the case of a malformed response.
      */
+    #[\ReturnTypeWillChange]
     public function getIterator()
     {
         return $this->readAll();
diff --git a/Bigtable/src/ResumableStream.php b/Bigtable/src/ResumableStream.php
index 8230c202ce37..ed1220cf266e 100644
--- a/Bigtable/src/ResumableStream.php
+++ b/Bigtable/src/ResumableStream.php
@@ -112,6 +112,7 @@ public function readAll()
      * @return \Generator
      * @throws ApiException Thrown in the case of a malformed response.
      */
+    #[\ReturnTypeWillChange]
     public function getIterator()
     {
         return $this->readAll();
diff --git a/Core/src/Iterator/ItemIteratorTrait.php b/Core/src/Iterator/ItemIteratorTrait.php
index 1236424b25b7..85fc65339c17 100644
--- a/Core/src/Iterator/ItemIteratorTrait.php
+++ b/Core/src/Iterator/ItemIteratorTrait.php
@@ -74,6 +74,7 @@ public function iterateByPage()
      *
      * @return null
      */
+    #[\ReturnTypeWillChange]
     public function rewind()
     {
         $this->pageIndex = 0;
@@ -86,6 +87,7 @@ public function rewind()
      *
      * @return mixed
      */
+    #[\ReturnTypeWillChange]
     public function current()
     {
         $page = $this->pageIterator->current();
@@ -100,6 +102,7 @@ public function current()
      *
      * @return int
      */
+    #[\ReturnTypeWillChange]
     public function key()
     {
         return $this->position;
@@ -110,6 +113,7 @@ public function key()
      *
      * @return null
      */
+    #[\ReturnTypeWillChange]
     public function next()
     {
         $this->pageIndex++;
@@ -126,6 +130,7 @@ public function next()
      *
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function valid()
     {
         $page = $this->pageIterator->current();
diff --git a/Core/src/Iterator/PageIteratorTrait.php b/Core/src/Iterator/PageIteratorTrait.php
index dd0de60356ef..bbf0ff8e1bd6 100644
--- a/Core/src/Iterator/PageIteratorTrait.php
+++ b/Core/src/Iterator/PageIteratorTrait.php
@@ -146,6 +146,7 @@ public function nextResultToken()
      *
      * @return null
      */
+    #[\ReturnTypeWillChange]
     public function rewind()
     {
         $this->itemCount = 0;
@@ -169,6 +170,7 @@ public function rewind()
      *
      * @return array|null
      */
+    #[\ReturnTypeWillChange]
     public function current()
     {
         if ($this->page === null) {
@@ -189,6 +191,7 @@ public function current()
      *
      * @return int
      */
+    #[\ReturnTypeWillChange]
     public function key()
     {
         return $this->position;
@@ -199,6 +202,7 @@ public function key()
      *
      * @return null
      */
+    #[\ReturnTypeWillChange]
     public function next()
     {
         $this->position++;
@@ -212,6 +216,7 @@ public function next()
      *
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function valid()
     {
         if (!$this->page && $this->position) {
diff --git a/Core/src/Testing/FileListFilterIterator.php b/Core/src/Testing/FileListFilterIterator.php
index 920e8566ecd1..f377c469a3c5 100644
--- a/Core/src/Testing/FileListFilterIterator.php
+++ b/Core/src/Testing/FileListFilterIterator.php
@@ -62,6 +62,7 @@ public function __construct(
      * @experimental
      * @internal
      */
+    #[\ReturnTypeWillChange]
     public function accept()
     {
         /** @var \SplFileInfo */
diff --git a/Core/src/Testing/Snippet/Coverage/ExcludeFilter.php b/Core/src/Testing/Snippet/Coverage/ExcludeFilter.php
index 6ca0bce0b65b..4ec41aafd8b0 100644
--- a/Core/src/Testing/Snippet/Coverage/ExcludeFilter.php
+++ b/Core/src/Testing/Snippet/Coverage/ExcludeFilter.php
@@ -44,6 +44,7 @@ public function __construct(Iterator $iterator, array $excludeDirs)
     /**
      * @return bool Determines whether to accept or exclude a path
      */
+    #[\ReturnTypeWillChange]
     public function accept()
     {
         // Accept the current item if we can recurse into it
diff --git a/Core/src/Testing/Snippet/Parser/Snippet.php b/Core/src/Testing/Snippet/Parser/Snippet.php
index 3499d75d1066..400aa64695da 100644
--- a/Core/src/Testing/Snippet/Parser/Snippet.php
+++ b/Core/src/Testing/Snippet/Parser/Snippet.php
@@ -291,6 +291,7 @@ public function regexReplace($pattern, $new)
      *
      * @return array
      */
+    #[\ReturnTypeWillChange]
     public function jsonSerialize()
     {
         return $this->config;
diff --git a/Datastore/src/DatastoreSessionHandler.php b/Datastore/src/DatastoreSessionHandler.php
index 7e8182be6dfc..3e9accfbecde 100644
--- a/Datastore/src/DatastoreSessionHandler.php
+++ b/Datastore/src/DatastoreSessionHandler.php
@@ -189,6 +189,7 @@ public function __construct(
      *        used here. It will use this value as the Datastore kind.
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function open($savePath, $sessionName)
     {
         $this->kind = $sessionName;
@@ -206,6 +207,7 @@ public function open($savePath, $sessionName)
     /**
      * Just return true for this implementation.
      */
+    #[\ReturnTypeWillChange]
     public function close()
     {
         return true;
@@ -214,6 +216,7 @@ public function close()
     /**
      * Read the session data from Cloud Datastore.
      */
+    #[\ReturnTypeWillChange]
     public function read($id)
     {
         try {
@@ -243,6 +246,7 @@ public function read($id)
      * @param string $data The session data to write to the {@see \Google\Cloud\Datastore\Entity}.
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function write($id, $data)
     {
         try {
@@ -274,6 +278,7 @@ public function write($id, $data)
     /**
      * Delete the session data from Cloud Datastore.
      */
+    #[\ReturnTypeWillChange]
     public function destroy($id)
     {
         try {
@@ -297,6 +302,7 @@ public function destroy($id)
     /**
      * Delete the old session data from Cloud Datastore.
      */
+    #[\ReturnTypeWillChange]
     public function gc($maxlifetime)
     {
         if ($this->gcLimit === 0) {
diff --git a/Datastore/src/Entity.php b/Datastore/src/Entity.php
index 70bdeda8fd5a..38c36fadf63e 100644
--- a/Datastore/src/Entity.php
+++ b/Datastore/src/Entity.php
@@ -113,6 +113,7 @@ class Entity implements ArrayAccess, EntityInterface
      * @return void
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function offsetSet($key, $val)
     {
         $this->entity[$key] = $val;
@@ -123,6 +124,7 @@ public function offsetSet($key, $val)
      * @return bool
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function offsetExists($key)
     {
         return isset($this->entity[$key]);
@@ -133,6 +135,7 @@ public function offsetExists($key)
      * @return void
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function offsetUnset($key)
     {
         unset($this->entity[$key]);
@@ -143,6 +146,7 @@ public function offsetUnset($key)
      * @return mixed
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($key)
     {
         return isset($this->entity[$key])
diff --git a/Datastore/src/EntityPageIterator.php b/Datastore/src/EntityPageIterator.php
index ea590ed3b574..0af78d977f97 100644
--- a/Datastore/src/EntityPageIterator.php
+++ b/Datastore/src/EntityPageIterator.php
@@ -51,6 +51,7 @@ public function moreResultsType()
      *
      * @return array|null
      */
+    #[\ReturnTypeWillChange]
     public function current()
     {
         if (!$this->page) {
diff --git a/Datastore/src/Key.php b/Datastore/src/Key.php
index 930d8fca5f78..778a2e2d2f1f 100644
--- a/Datastore/src/Key.php
+++ b/Datastore/src/Key.php
@@ -421,6 +421,7 @@ public function keyObject()
     /**
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function jsonSerialize()
     {
         return $this->keyObject();
diff --git a/Datastore/src/Query/GqlQuery.php b/Datastore/src/Query/GqlQuery.php
index 8cf7938d306e..91eafc3c6a80 100644
--- a/Datastore/src/Query/GqlQuery.php
+++ b/Datastore/src/Query/GqlQuery.php
@@ -214,6 +214,7 @@ public function start($cursor)
      * @access private
      * @return array
      */
+    #[\ReturnTypeWillChange]
     public function jsonSerialize()
     {
         return $this->queryObject();
diff --git a/Datastore/src/Query/Query.php b/Datastore/src/Query/Query.php
index 8b7fe70ebc7a..6f67a2d29d82 100644
--- a/Datastore/src/Query/Query.php
+++ b/Datastore/src/Query/Query.php
@@ -476,6 +476,7 @@ public function queryKey()
     /**
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function jsonSerialize()
     {
         return $this->queryObject();
diff --git a/Datastore/tests/Unit/SampleEntity.php b/Datastore/tests/Unit/SampleEntity.php
index 04c0cc1c1567..a2a88f1337ea 100644
--- a/Datastore/tests/Unit/SampleEntity.php
+++ b/Datastore/tests/Unit/SampleEntity.php
@@ -33,21 +33,25 @@ public static function mappings()
         ];
     }
 
+    #[\ReturnTypeWillChange]
     public function offsetSet($key, $val)
     {
         $this->entity[$key] = $val;
     }
 
+    #[\ReturnTypeWillChange]
     public function offsetExists($key)
     {
         return isset($this->entity[$key]);
     }
 
+    #[\ReturnTypeWillChange]
     public function offsetUnset($key)
     {
         unset($this->entity[$key]);
     }
 
+    #[\ReturnTypeWillChange]
     public function offsetGet($key)
     {
         return isset($this->entity[$key])
diff --git a/Debugger/src/MatchingFileIterator.php b/Debugger/src/MatchingFileIterator.php
index 992c3dbda1f5..4673586e7454 100644
--- a/Debugger/src/MatchingFileIterator.php
+++ b/Debugger/src/MatchingFileIterator.php
@@ -62,6 +62,7 @@ public function __construct($searchPath, $file)
      * @access private
      * @return boolean
      */
+    #[\ReturnTypeWillChange]
     public function accept()
     {
         $candidate = $this->getInnerIterator()->current();
diff --git a/Firestore/src/DocumentSnapshot.php b/Firestore/src/DocumentSnapshot.php
index 9a6d234219cf..0d03e4b92985 100644
--- a/Firestore/src/DocumentSnapshot.php
+++ b/Firestore/src/DocumentSnapshot.php
@@ -310,6 +310,7 @@ public function get($fieldPath)
     /**
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function offsetSet($offset, $value)
     {
         throw new \BadMethodCallException('DocumentSnapshots are read-only.');
@@ -318,6 +319,7 @@ public function offsetSet($offset, $value)
     /**
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function offsetExists($offset)
     {
         return array_key_exists($offset, $this->data);
@@ -326,6 +328,7 @@ public function offsetExists($offset)
     /**
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function offsetUnset($offset)
     {
         throw new \BadMethodCallException('DocumentSnapshots are read-only.');
@@ -334,6 +337,7 @@ public function offsetUnset($offset)
     /**
      * @access private
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($offset)
     {
         if (!$this->offsetExists($offset)) {
diff --git a/Firestore/src/FirestoreSessionHandler.php b/Firestore/src/FirestoreSessionHandler.php
index 5d07f40920e2..832a4cd84d50 100644
--- a/Firestore/src/FirestoreSessionHandler.php
+++ b/Firestore/src/FirestoreSessionHandler.php
@@ -211,6 +211,7 @@ public function __construct(
      *        used in the Firestore collection ID.
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function open($savePath, $sessionName)
     {
         $this->savePath = $savePath;
@@ -241,6 +242,7 @@ public function open($savePath, $sessionName)
     /**
      * Close the transaction and commit any changes.
      */
+    #[\ReturnTypeWillChange]
     public function close()
     {
         if (is_null($this->transaction)) {
@@ -264,6 +266,7 @@ public function close()
      * @param string $id Identifier used for the session.
      * @return string
      */
+    #[\ReturnTypeWillChange]
     public function read($id)
     {
         $this->id = $id;
@@ -298,6 +301,7 @@ public function read($id)
      * @param string $data The session data to write to the Firestore document.
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function write($id, $data)
     {
         $docRef = $this->getDocumentReference(
@@ -320,6 +324,7 @@ public function write($id, $data)
      * @param string $id Identifier used for the session
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function destroy($id)
     {
         $docRef = $this->getDocumentReference(
@@ -340,6 +345,7 @@ public function destroy($id)
      *        in seconds.
      * @return int|bool
      */
+    #[\ReturnTypeWillChange]
     public function gc($maxlifetime)
     {
         if (0 === $this->options['gcLimit']) {
diff --git a/Firestore/src/QuerySnapshot.php b/Firestore/src/QuerySnapshot.php
index 0a73440ab574..d151aea3d1c4 100644
--- a/Firestore/src/QuerySnapshot.php
+++ b/Firestore/src/QuerySnapshot.php
@@ -112,6 +112,7 @@ public function rows()
      * @access private
      * @return \ArrayIterator
      */
+    #[\ReturnTypeWillChange]
     public function getIterator()
     {
         return new \ArrayIterator($this->rows);
diff --git a/Spanner/src/Result.php b/Spanner/src/Result.php
index 94538825e130..1275f5716722 100644
--- a/Spanner/src/Result.php
+++ b/Spanner/src/Result.php
@@ -374,6 +374,7 @@ public function transaction()
      * @access private
      * @return \Generator
      */
+    #[\ReturnTypeWillChange]
     public function getIterator()
     {
         return $this->rows();
diff --git a/Storage/src/Lifecycle.php b/Storage/src/Lifecycle.php
index 168dc5e3250d..66f4ee228025 100644
--- a/Storage/src/Lifecycle.php
+++ b/Storage/src/Lifecycle.php
@@ -304,6 +304,7 @@ public function clearRules($action = null)
      * @access private
      * @return \Generator
      */
+    #[\ReturnTypeWillChange]
     public function getIterator()
     {
         if (!isset($this->lifecycle['rule'])) {
@@ -329,6 +330,7 @@ public function toArray()
      * @param string $offset
      * @param mixed $value
      */
+    #[\ReturnTypeWillChange]
     public function offsetSet($offset, $value)
     {
         $this->lifecycle['rule'][$offset] = $value;
@@ -339,6 +341,7 @@ public function offsetSet($offset, $value)
      * @param string $offset
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function offsetExists($offset)
     {
         return isset($this->lifecycle['rule'][$offset]);
@@ -348,6 +351,7 @@ public function offsetExists($offset)
      * @access private
      * @param string $offset
      */
+    #[\ReturnTypeWillChange]
     public function offsetUnset($offset)
     {
         unset($this->lifecycle['rule'][$offset]);
@@ -358,6 +362,7 @@ public function offsetUnset($offset)
      * @param string $offset
      * @return mixed
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($offset)
     {
         return isset($this->lifecycle['rule'][$offset])
diff --git a/Storage/src/ObjectPageIterator.php b/Storage/src/ObjectPageIterator.php
index ecf1b3685f72..3e4e4a00e88b 100644
--- a/Storage/src/ObjectPageIterator.php
+++ b/Storage/src/ObjectPageIterator.php
@@ -48,6 +48,7 @@ public function prefixes()
      *
      * @return array|null
      */
+    #[\ReturnTypeWillChange]
     public function current()
     {
         if (!$this->page) {
diff --git a/Trace/src/Attributes.php b/Trace/src/Attributes.php
index 98e0815d6cb6..df75b6b8b9e3 100644
--- a/Trace/src/Attributes.php
+++ b/Trace/src/Attributes.php
@@ -51,6 +51,7 @@ class Attributes implements \ArrayAccess
      * @param string $offset
      * @param mixed $value
      */
+    #[\ReturnTypeWillChange]
     public function offsetSet($offset, $value)
     {
         $this->attributes[$offset] = $value;
@@ -62,6 +63,7 @@ public function offsetSet($offset, $value)
      * @access private
      * @param string $offset
      */
+    #[\ReturnTypeWillChange]
     public function offsetExists($offset)
     {
         return isset($this->attributes[$offset]);
@@ -73,6 +75,7 @@ public function offsetExists($offset)
      * @access private
      * @param string $offset
      */
+    #[\ReturnTypeWillChange]
     public function offsetUnset($offset)
     {
         unset($this->attributes[$offset]);
@@ -84,6 +87,7 @@ public function offsetUnset($offset)
      * @access private
      * @param string $offset
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($offset)
     {
         return isset($this->attributes[$offset])