diff --git a/composer.json b/composer.json
index 75407ee..90bd511 100644
--- a/composer.json
+++ b/composer.json
@@ -8,7 +8,7 @@
         }
     },
     "require"    : {
-        "php": ">=5.4"
+        "php": "^5.3.10|^7.0"
     },
     "require-dev": {
         "php": ">=5.6",