diff --git a/composer.json b/composer.json
index 7e1ca42..feff976 100644
--- a/composer.json
+++ b/composer.json
@@ -10,6 +10,7 @@
         }
     ],
     "require": {
+        "php": "^7.1",
         "symfony/config": "^3.4",
         "symfony/console": "^3.4",
         "symfony/dependency-injection": "^3.4",