diff --git a/.travis.yml b/.travis.yml
index 4f66147..916b48c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,6 @@
 language: node_js
 node_js:
   - stable
+  - "10"
+  - "8"
   - "6"
-  - "4"
diff --git a/package.json b/package.json
index dc5d4fe..ebeadd1 100644
--- a/package.json
+++ b/package.json
@@ -16,16 +16,16 @@
   ],
   "main": "lib/pixrem.js",
   "engines": {
-    "node": ">=0.10.0",
+    "node": ">=4.0.0",
     "npm": ">=1.2.10"
   },
   "scripts": {
     "test": "mocha"
   },
   "dependencies": {
-    "browserslist": "^2.0.0",
-    "postcss": "^6.0.0",
-    "reduce-css-calc": "^1.2.7"
+    "browserslist": "^4.3.6",
+    "postcss": "^7.0.7",
+    "reduce-css-calc": "^2.1.5"
   },
   "devDependencies": {
     "mocha": "^2.3.2"