diff --git a/.travis.yml b/.travis.yml
index f3252441..7e314a1b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,8 @@ language: node_js
 node_js:
   - "node"
   - "8"
+  - "6"
+  - "4"
 install:
   - npm install
   - npm install -g grunt-cli
diff --git a/package.json b/package.json
index d04c4bf2..3502ec17 100644
--- a/package.json
+++ b/package.json
@@ -31,7 +31,7 @@
 		"moment": ">= 2.9.0"
 	},
 	"devDependencies": {
-		"grunt": "^1.0.4",
+		"grunt": "1.0.4",
 		"grunt-contrib-clean": "^2.0.0",
 		"grunt-contrib-jshint": "^2.1.0",
 		"grunt-contrib-nodeunit": "^2.0.0",