diff --git a/.npmrc b/.npmrc
new file mode 100644
index 0000000..9cf9495
--- /dev/null
+++ b/.npmrc
@@ -0,0 +1 @@
+package-lock=false
\ No newline at end of file
diff --git a/.travis.yml b/.travis.yml
index 47aad24..4f05640 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,7 @@
 language: node_js
 node_js:
+- '8'
 - '6'
-- '5'
-- '4.2'
 
 script: npm run citest
 after_script: npm install coveralls@^2.11.9 && cat ./coverage/lcov.info | coveralls
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0db4d63..6d9ea93 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,8 @@ All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
+### Changed
+- Update node to v6/v8 and upgrade modules
 
 
 ## [v0.4.0]
diff --git a/ElasticLoader.spec.ts b/ElasticLoader.spec.ts
index 220d719..d045c63 100644
--- a/ElasticLoader.spec.ts
+++ b/ElasticLoader.spec.ts
@@ -20,7 +20,7 @@ describe('ElasticLoader', () => {
             index: o => Observable.of(o)
         };
 
-        stub = sinon.stub(client, 'index', o => Observable.of(o));
+        stub = sinon.stub(client, 'index').callsFake(o => Observable.of(o));
     });
 
     it('should resolve on correct usage', done => {
diff --git a/helpers/Buffer.ts b/helpers/Buffer.ts
index db7855e..90de9ff 100644
--- a/helpers/Buffer.ts
+++ b/helpers/Buffer.ts
@@ -61,7 +61,7 @@ export class Buffer<T> extends EventEmitter {
         });
     }
 
-    public write(object: T): Promise<T> | Promise<void> {
+    public write(object: T): Promise<T | undefined> {
         if (this.sealed) {
             return Promise.reject(new BufferSealedError());
         }
diff --git a/package.json b/package.json
index 5f15ad9..ae2182b 100644
--- a/package.json
+++ b/package.json
@@ -5,7 +5,7 @@
   "main": "index.js",
   "scripts": {
     "clean": "rimraf build",
-    "bootstrap": "npm install && typings install",
+    "bootstrap": "npm install",
     "pretest": "npm run bootstrap && npm run clean && tsc",
     "test": "mocha --ui bdd --recursive ./build",
     "precitest": "npm run bootstrap && npm run clean && tsc",
@@ -21,7 +21,7 @@
     "elasticsearch"
   ],
   "engines": {
-    "node": ">=4.2"
+    "node": ">=6"
   },
   "repository": {
     "type": "git",
@@ -31,21 +31,26 @@
   "author": "Christoph Bühler <christoph.buehler@bluewin.ch>",
   "license": "MIT",
   "devDependencies": {
-    "chai": "^3.5.0",
-    "chai-as-promised": "^5.3.0",
-    "del-cli": "^0.2.0",
+    "@types/chai": "^4.0.1",
+    "@types/chai-as-promised": "^0.0.31",
+    "@types/mocha": "^2.2.41",
+    "@types/node": "^8.0.16",
+    "@types/sinon": "^2.3.3",
+    "@types/sinon-chai": "^2.7.28",
+    "chai": "^4.1.0",
+    "chai-as-promised": "^7.1.1",
+    "del-cli": "^1.1.0",
     "istanbul": "^0.4.4",
-    "mocha": "^2.5.3",
+    "mocha": "^3.4.1",
     "mocha-lcov-reporter": "^1.2.0",
     "rimraf": "^2.5.3",
-    "sinon": "^1.17.4",
+    "sinon": "^2.4.0",
     "sinon-chai": "^2.8.0",
-    "typescript": "^1.8.10",
-    "typings": "^1.3.1"
+    "typescript": "^2.4.2"
   },
   "dependencies": {
-    "elasticsearch": "^11.0.1",
+    "elasticsearch": "^13.2.0",
     "proc-that": "^0.4.0",
-    "rxjs": "^5.0.0-beta.10"
+    "rxjs": "^5.4.2"
   }
 }
diff --git a/tsconfig.json b/tsconfig.json
index d9bee7e..a63e4e0 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "target": "es5",
+    "target": "es6",
     "module": "commonjs",
     "moduleResolution": "node",
     "removeComments": false,
diff --git a/typings.json b/typings.json
deleted file mode 100644
index 5edf886..0000000
--- a/typings.json
+++ /dev/null
@@ -1,17 +0,0 @@
-{
-  "name": "proc-that-elastic-loader",
-  "dependencies": {},
-  "globalDependencies": {
-    "es6-shim": "registry:dt/es6-shim#0.31.2+20160602141504",
-    "node": "registry:dt/node#6.0.0+20160709114037"
-  },
-  "globalDevDependencies": {
-    "mocha": "registry:dt/mocha#2.2.5+20160619032855"
-  },
-  "devDependencies": {
-    "chai": "registry:npm/chai#3.5.0+20160415060238",
-    "chai-as-promised": "registry:npm/chai-as-promised#5.1.0+20160310030142",
-    "sinon": "registry:npm/sinon#1.16.0+20160427193336",
-    "sinon-chai": "registry:npm/sinon-chai#2.8.0+20160310030142"
-  }
-}
\ No newline at end of file