diff --git a/.travis.yml b/.travis.yml
index 895dbd3..5346f6e 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,4 +1,7 @@
 language: node_js
 node_js:
-  - 0.6
-  - 0.8
+  - "node"
+  - "6"
+  - "4"
+  - "0.12"
+  - "0.10" 
diff --git a/index.js b/index.js
index 4f45b70..69b7d79 100644
--- a/index.js
+++ b/index.js
@@ -2,11 +2,9 @@ module.exports = function deepFreeze (o) {
   Object.freeze(o);
 
   var oIsFunction = typeof o === "function";
-  var hasOwnProp = Object.prototype.hasOwnProperty;
 
   Object.getOwnPropertyNames(o).forEach(function (prop) {
-    if (hasOwnProp.call(o, prop)
-    && (oIsFunction ? prop !== 'caller' && prop !== 'callee' && prop !== 'arguments' : true )
+    if ((oIsFunction ? prop !== 'caller' && prop !== 'callee' && prop !== 'arguments' : true )
     && o[prop] !== null
     && (typeof o[prop] === "object" || typeof o[prop] === "function")
     && !Object.isFrozen(o[prop])) {