diff --git a/.travis.yml b/.travis.yml
index 9a53819..a349569 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,6 @@
 language: node_js
 node_js:
-  - "1.0"
-  - "2.0"
+  - "4.0"
 
 before_script:
-  coffee -c -o ./lib ./src
\ No newline at end of file
+  coffee -c -o ./lib ./src
diff --git a/README.md b/README.md
index d1d337f..a42f1f0 100644
--- a/README.md
+++ b/README.md
@@ -36,6 +36,8 @@ sim(document.body).do ->
 
 ### Server-side Usage
 
+**IMPORTANT: Requires Node.js 4.0+**
+
 ```coffeescript
 sim = require 'simdom'
 
diff --git a/package.json b/package.json
index 436364b..ae897e6 100644
--- a/package.json
+++ b/package.json
@@ -26,7 +26,7 @@
     "mocha": "^2.1.0"
   },
   "engines": {
-    "node": ">=0.10"
+    "node": ">=4.00"
   },
   "scripts": {
     "prepublish": "coffee -c -o ./lib ./src",