diff --git a/.travis.yml b/.travis.yml
index a997c30..67bce8d 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -2,6 +2,5 @@ language: node_js
 node_js:
   - '8'
   - '6'
-  - '4'
 after_script:
   - './node_modules/.bin/nyc report --reporter=text-lcov > coverage.lcov && ./node_modules/.bin/codecov'
diff --git a/package.json b/package.json
index 1f46d0d..e55f216 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
 	},
 	"main": "dist/index.js",
 	"engines": {
-		"node": ">=4"
+		"node": ">=6"
 	},
 	"scripts": {
 		"prerelease": "npm run build",
diff --git a/tsconfig.json b/tsconfig.json
index f6bdaa8..435ac2b 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,7 +1,7 @@
 {
 	"compilerOptions": {
 		"outDir": "dist",
-		"target": "es5",
+		"target": "es2015",
 		"lib": [
 			"es2015"
 		],