diff --git a/.travis.yml b/.travis.yml
index 4887a00..8196865 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,6 +11,7 @@ notifications:
 node_js:
   - 'node'
   - '7'
+  - '6'
 before_script:
   - npm prune
 after_success:
diff --git a/package.json b/package.json
index 5c9fbc3..60568b3 100644
--- a/package.json
+++ b/package.json
@@ -11,6 +11,10 @@
     "test": "npm run compile && mocha",
     "generate-docs": "node_modules/.bin/jsdoc --configure .jsdoc.json --verbose"
   },
+  "engines": {
+    "node": ">=6",
+    "npm": ">=4"
+  },
   "keywords": [
     "torrent",
     "library",