diff --git a/composer.json b/composer.json
index 6092bc5..55842be 100644
--- a/composer.json
+++ b/composer.json
@@ -10,7 +10,7 @@
   ],
   "require": {
     "php": ">=5.4.0",
-    "guzzlehttp/guzzle": "~4.1",
+    "guzzlehttp/guzzle": "~5.0",
     "symfony/serializer": "~2.4",
     "packaged/helpers": "~0",
     "packaged/docblock": "~0",