diff --git a/composer.json b/composer.json
index f24cd55..a25fc18 100644
--- a/composer.json
+++ b/composer.json
@@ -15,6 +15,6 @@
         }
     ],
     "require": {
-        "php": ">=5.6"
+        "php": ">=5.1"
     }
 }