diff --git a/composer.json b/composer.json
index 9d3798c..d95217d 100644
--- a/composer.json
+++ b/composer.json
@@ -1,9 +1,6 @@
 {
   "require" : {
-	"php" : "^7.1.9",
-	"ext-mbstring": "^7.1"
-  },
-  "require-dev": {
-    "heroku/heroku-buildpack-php": "*"
+	"php" : "^5.5",
+	"ext-mbstring": "*"
   }
 }