diff --git a/composer.json b/composer.json
index ea5b1fd..694e07f 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,7 @@
         }
     ],
     "require": {
-        "php": "^5.5 || ^7.0",
+        "php": "^5.6 || ^7.0",
         "psr/cache": "^1.0",
         "psr/simple-cache": "^1.0"
     },