diff --git a/composer.json b/composer.json
index c4e4f5ef..7b628fa6 100644
--- a/composer.json
+++ b/composer.json
@@ -105,6 +105,9 @@
         ]
     },
     "config": {
+        "platform": {
+            "php": "5.6.4"
+        },
         "preferred-install": "dist",
         "sort-packages": true,
         "optimize-autoloader": true