Drop node 4

README.md

@@ -34,7 +34,7 @@ https://thegecko.github.io/web-bluetooth-dfu/
 
 ## Prerequisites
 
-[Node.js > v4.8.0](https://nodejs.org), which includes `npm`.
+[Node.js > v6.15.0](https://nodejs.org), which includes `npm`.
 
 ## Installation
 

circle.yml

@@ -3,7 +3,7 @@ version: 2
 jobs:
   build:
     docker:
-      - image: circleci/node:4.8.0
+      - image: circleci/node:6.15.0
     steps:
       - checkout
       - run: npm install
@@ -15,7 +15,7 @@ jobs:
 
   deploy:
     docker:
-      - image: circleci/node:4.8.0
+      - image: circleci/node:6.15.0
     steps:
       - attach_workspace:
           at: ../

package.json

@@ -28,7 +28,7 @@
     "example": "node examples/node.js"
   },
   "engines": {
-    "node": ">=4.8.0"
+    "node": ">=6.15.0"
   },
   "dependencies": {
     "@types/node": "^8.0.54",