diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MigratingSessionHandler.php b/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MigratingSessionHandler.php
index c6b16d11c8..c3e7ef6e60 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MigratingSessionHandler.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/MigratingSessionHandler.php
@@ -41,6 +41,7 @@ class MigratingSessionHandler implements \SessionHandlerInterface, \SessionUpdat
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function close()
     {
         $result = $this->currentHandler->close();
@@ -52,6 +53,7 @@ class MigratingSessionHandler implements \SessionHandlerInterface, \SessionUpdat
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function destroy($sessionId)
     {
         $result = $this->currentHandler->destroy($sessionId);
@@ -63,6 +65,7 @@ class MigratingSessionHandler implements \SessionHandlerInterface, \SessionUpdat
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function gc($maxlifetime)
     {
         $result = $this->currentHandler->gc($maxlifetime);
@@ -74,6 +77,7 @@ class MigratingSessionHandler implements \SessionHandlerInterface, \SessionUpdat
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function open($savePath, $sessionName)
     {
         $result = $this->currentHandler->open($savePath, $sessionName);
@@ -85,6 +89,7 @@ class MigratingSessionHandler implements \SessionHandlerInterface, \SessionUpdat
     /**
      * @return string
      */
+    #[\ReturnTypeWillChange]
     public function read($sessionId)
     {
         // No reading from new handler until switch-over
@@ -94,6 +99,7 @@ class MigratingSessionHandler implements \SessionHandlerInterface, \SessionUpdat
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function write($sessionId, $sessionData)
     {
         $result = $this->currentHandler->write($sessionId, $sessionData);
@@ -105,6 +111,7 @@ class MigratingSessionHandler implements \SessionHandlerInterface, \SessionUpdat
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function validateId($sessionId)
     {
         // No reading from new handler until switch-over
@@ -114,6 +121,7 @@ class MigratingSessionHandler implements \SessionHandlerInterface, \SessionUpdat
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function updateTimestamp($sessionId, $sessionData)
     {
         $result = $this->currentHandler->updateTimestamp($sessionId, $sessionData);
diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/NullSessionHandler.php b/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/NullSessionHandler.php
index 0634e46dd5..c34c25edbb 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/NullSessionHandler.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/NullSessionHandler.php
@@ -21,6 +21,7 @@ class NullSessionHandler extends AbstractSessionHandler
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function close()
     {
         return true;
@@ -29,6 +30,7 @@ class NullSessionHandler extends AbstractSessionHandler
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function validateId($sessionId)
     {
         return true;
@@ -45,6 +47,7 @@ class NullSessionHandler extends AbstractSessionHandler
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function updateTimestamp($sessionId, $data)
     {
         return true;
@@ -69,6 +72,7 @@ class NullSessionHandler extends AbstractSessionHandler
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function gc($maxlifetime)
     {
         return true;
diff --git a/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php b/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php
index db74187760..d3c5651d41 100644
--- a/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php
+++ b/src/Symfony/Component/HttpFoundation/Session/Storage/Handler/PdoSessionHandler.php
@@ -262,6 +262,7 @@ class PdoSessionHandler extends AbstractSessionHandler
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function open($savePath, $sessionName)
     {
         $this->sessionExpired = false;
@@ -276,6 +277,7 @@ class PdoSessionHandler extends AbstractSessionHandler
     /**
      * @return string
      */
+    #[\ReturnTypeWillChange]
     public function read($sessionId)
     {
         try {
@@ -290,6 +292,7 @@ class PdoSessionHandler extends AbstractSessionHandler
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function gc($maxlifetime)
     {
         // We delay gc() to close() so that it is executed outside the transactional and blocking read-write process.
@@ -369,6 +372,7 @@ class PdoSessionHandler extends AbstractSessionHandler
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function updateTimestamp($sessionId, $data)
     {
         $expiry = time() + (int) ini_get('session.gc_maxlifetime');
@@ -393,6 +397,7 @@ class PdoSessionHandler extends AbstractSessionHandler
     /**
      * @return bool
      */
+    #[\ReturnTypeWillChange]
     public function close()
     {
         $this->commit();
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MigratingSessionHandlerTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MigratingSessionHandlerTest.php
index 01615e6b1f..f56f753af6 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MigratingSessionHandlerTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/MigratingSessionHandlerTest.php
@@ -75,15 +75,14 @@ class MigratingSessionHandlerTest extends TestCase
         $this->currentHandler->expects($this->once())
             ->method('gc')
             ->with($maxlifetime)
-            ->willReturn(true);
+            ->willReturn(1);
 
         $this->writeOnlyHandler->expects($this->once())
             ->method('gc')
             ->with($maxlifetime)
             ->willReturn(false);
 
-        $result = $this->dualHandler->gc($maxlifetime);
-        $this->assertTrue($result);
+        $this->assertSame(1, $this->dualHandler->gc($maxlifetime));
     }
 
     public function testOpen()
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/PdoSessionHandlerTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/PdoSessionHandlerTest.php
index c731180916..79ab73c1a4 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/PdoSessionHandlerTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/PdoSessionHandlerTest.php
@@ -371,6 +371,10 @@ class MockPdo extends \PDO
         $this->errorMode = null !== $errorMode ?: \PDO::ERRMODE_EXCEPTION;
     }
 
+    /**
+     * @return mixed
+     */
+    #[\ReturnTypeWillChange]
     public function getAttribute($attribute)
     {
         if (\PDO::ATTR_ERRMODE === $attribute) {
@@ -384,6 +388,10 @@ class MockPdo extends \PDO
         return parent::getAttribute($attribute);
     }
 
+    /**
+     * @return false|\PDOStatement
+     */
+    #[\ReturnTypeWillChange]
     public function prepare($statement, $driverOptions = [])
     {
         return \is_callable($this->prepareResult)
@@ -391,11 +399,13 @@ class MockPdo extends \PDO
             : $this->prepareResult;
     }
 
-    public function beginTransaction()
+    public function beginTransaction(): bool
     {
+        return true;
     }
 
-    public function rollBack()
+    public function rollBack(): bool
     {
+        return true;
     }
 }
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/StrictSessionHandlerTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/StrictSessionHandlerTest.php
index 353b1a02ec..4f91016ac5 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/StrictSessionHandlerTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/StrictSessionHandlerTest.php
@@ -181,9 +181,9 @@ class StrictSessionHandlerTest extends TestCase
     {
         $handler = $this->createMock(\SessionHandlerInterface::class);
         $handler->expects($this->once())->method('gc')
-            ->with(123)->willReturn(true);
+            ->with(123)->willReturn(1);
         $proxy = new StrictSessionHandler($handler);
 
-        $this->assertTrue($proxy->gc(123));
+        $this->assertSame(1, $proxy->gc(123));
     }
 }
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Proxy/SessionHandlerProxyTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Proxy/SessionHandlerProxyTest.php
index 27bf3e27a6..1422eccfbc 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Proxy/SessionHandlerProxyTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Proxy/SessionHandlerProxyTest.php
@@ -93,7 +93,9 @@ class SessionHandlerProxyTest extends TestCase
     public function testRead()
     {
         $this->mock->expects($this->once())
-            ->method('read');
+            ->method('read')
+            ->willReturn('foo')
+        ;
 
         $this->proxy->read('id');
     }
@@ -117,7 +119,9 @@ class SessionHandlerProxyTest extends TestCase
     public function testGc()
     {
         $this->mock->expects($this->once())
-            ->method('gc');
+            ->method('gc')
+            ->willReturn(1)
+        ;
 
         $this->proxy->gc(86400);
     }