You can now develop your AWS Lambda functions using Node.js 4.3.2 in addition to Node.js 0.10.4. In addition to the leveraging new features in Node.js 4.3 such as ES6 support , Lambda functions written in Node.js 4.3 can now use standard Node.js callback conventions to specify error or return values for the function execution. Previously, returning values from a Lambda function required the use of methods specific to the Lambda programming model. See our documentation to learn more about implementing callbacks within Lambda functions.