diff --git a/composer.json b/composer.json
index 411836ff7..62346fa35 100644
--- a/composer.json
+++ b/composer.json
@@ -25,7 +25,7 @@
         }
     },
     "require": {
-        "php": "^5.6 || ^7.0",
+        "php": "^7.2",
         "laminas/laminas-eventmanager": "^2.6.2 || ^3.0",
         "laminas/laminas-json": "^2.6.1 || ^3.0",
         "laminas/laminas-loader": "^2.5",
diff --git a/src/Helper/HeadScript.php b/src/Helper/HeadScript.php
index 8a235f2f0..8bac922a1 100644
--- a/src/Helper/HeadScript.php
+++ b/src/Helper/HeadScript.php
@@ -33,7 +33,7 @@ class HeadScript extends Placeholder\Container\AbstractStandalone
      */
     const FILE   = 'FILE';
     const SCRIPT = 'SCRIPT';
-    const DEFAULT_SCRIPT_TYPE = 'text/javascript';
+    private const DEFAULT_SCRIPT_TYPE = 'text/javascript';
 
     /**
      * Are arbitrary attributes allowed?