diff --git a/src/Symfony/Component/Serializer/composer.json b/src/Symfony/Component/Serializer/composer.json
index 8872215af0..458a5a5cf1 100644
--- a/src/Symfony/Component/Serializer/composer.json
+++ b/src/Symfony/Component/Serializer/composer.json
@@ -17,7 +17,7 @@
     ],
     "require": {
         "php": ">=5.3.9",
-        "symfony/polyfill-php54": "~1.0"
+        "symfony/polyfill-php55": "~1.0"
     },
     "require-dev": {
         "symfony/yaml": "~2.0,>=2.0.5|~3.0.0",