diff --git a/composer.json b/composer.json
index a6bfaba..1f8fa66 100644
--- a/composer.json
+++ b/composer.json
@@ -17,6 +17,9 @@
             "role": "Developer"
         }
     ],
+    "require": {
+        "php": ">=5.5.0"
+    },
     "autoload": {
         "psr-4": {
             "SadeghPM\\Recapcha\\": "src"