diff --git a/src/Symfony/Component/Serializer/Serializer.php b/src/Symfony/Component/Serializer/Serializer.php
index 1e4fb793e8..08f8e960ff 100644
--- a/src/Symfony/Component/Serializer/Serializer.php
+++ b/src/Symfony/Component/Serializer/Serializer.php
@@ -169,7 +169,7 @@ class Serializer implements SerializerInterface, ContextAwareNormalizerInterface
                 switch (true) {
                     case ($context[AbstractObjectNormalizer::PRESERVE_EMPTY_OBJECTS] ?? false) && \is_object($data):
                         if (!$data instanceof \ArrayObject) {
-                            trigger_deprecation('symfony/serializer', '5.4', 'The method "%s()" will return an instance of "%s" as of Symfony 6.0 when the object is iteratable, countable and empty.', __METHOD__, \ArrayObject::class);
+                            trigger_deprecation('symfony/serializer', '5.4', 'Returning empty object of class "%s" from "%s()" is deprecated unless it extends "ArrayObject".', get_debug_type($data), __METHOD__);
                         }
 
                         return $data;
diff --git a/src/Symfony/Component/Serializer/Tests/SerializerTest.php b/src/Symfony/Component/Serializer/Tests/SerializerTest.php
index 2afbd51c22..ab74b06ab0 100644
--- a/src/Symfony/Component/Serializer/Tests/SerializerTest.php
+++ b/src/Symfony/Component/Serializer/Tests/SerializerTest.php
@@ -578,10 +578,7 @@ class SerializerTest extends TestCase
         $this->assertSame($expected, $serializer->serialize($data, 'json'));
     }
 
-    /**
-     * @dataProvider provideObjectOrCollectionTests
-     * @group legacy
-     */
+    /** @dataProvider provideObjectOrCollectionTests */
     public function testNormalizePreserveEmptyArrayObject(Serializer $serializer, array $data)
     {
         $expected = '{"a1":{},"a2":{"k":"v"},"b1":[],"b2":{"k":"v"},"c1":{"nested":{}},"c2":{"nested":{"k":"v"}},"d1":{"nested":[]},"d2":{"nested":{"k":"v"}},"e1":{"map":[]},"e2":{"map":{"k":"v"}},"f1":{"map":{}},"f2":{"map":{"k":"v"}},"g1":{"list":{"list":[]},"settings":[]},"g2":{"list":["greg"],"settings":[]}}';
@@ -599,10 +596,7 @@ class SerializerTest extends TestCase
         ]));
     }
 
-    /**
-     * @dataProvider provideObjectOrCollectionTests
-     * @group legacy
-     */
+    /** @dataProvider provideObjectOrCollectionTests */
     public function testNormalizeEmptyArrayAsObjectAndPreserveEmptyArrayObject(Serializer $serializer, array $data)
     {
         $expected = '{"a1":{},"a2":{"k":"v"},"b1":{},"b2":{"k":"v"},"c1":{"nested":{}},"c2":{"nested":{"k":"v"}},"d1":{"nested":{}},"d2":{"nested":{"k":"v"}},"e1":{"map":{}},"e2":{"map":{"k":"v"}},"f1":{"map":{}},"f2":{"map":{"k":"v"}},"g1":{"list":{"list":[]},"settings":{}},"g2":{"list":["greg"],"settings":{}}}';
@@ -797,13 +791,15 @@ class Baz
     }
 }
 
-class DummyList implements \Countable, \IteratorAggregate
+class DummyList extends \ArrayObject
 {
     public $list;
 
     public function __construct(array $list)
     {
         $this->list = $list;
+
+        $this->setFlags(\ArrayObject::STD_PROP_LIST);
     }
 
     public function count(): int