diff --git a/composer.json b/composer.json
index d34e36b..674fd48 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
     "minimum-stability": "stable",
     "require": {
         "php": ">=5.4.0",
-        "guzzlehttp/guzzle": ">=4.2,<6.0"
+        "guzzlehttp/guzzle": ">=4.2,<6.5"
     },
     "require-dev": {
         "phpunit/phpunit": "4.2.*",