diff --git a/composer.json b/composer.json
index ead5c5e..02cfd9d 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
         }
     ],
     "require": {
-        "php": ">=5.5.0",
+        "php": "^7||^5.5",
         "ext-mbstring": "*"
     },
     "require-dev": {