Announced via a blog post, the Node.js team wrote:
The collaborators of the Node.js project and the members of the Node.js Foundation are proud to offer v4.0.0 for general release. This release represents countless hours of hard work encapsulated in both the Node.js project and the io.js project that are now combined in a single codebase. The Node.js project is now operated by a team of 44 collaborators, 15 of which form its Technical Steering Committee (TSC). Further, over 100 new individuals have been added to the list of people contributing code to core since v0.12.7.
Download Node.js 4.0.0: https://new.nodejs.org
Some of the key improvements and features in this version include:
New ES6 features including block scoping, classes, typed arrays, generators, Promises, Symbols, template strings, collections and, new to V8 v4.5, arrow functions.
Node.js now have first-class support for ARM processors.
Node.js v4 also brings a plan for long-term support (LTS) and a regular release cycle.