Facebook has released React v0.13, bringing with it support for ES6 classes, as well as new top-level APIs and breaking changes for JSX.
CoffeeScript 1.9 has finally introduced support for long awaited generators, which promise to prevent callback hell and help writing async code.
The io.js team has released version 1.0 -- but the versioning does not suggest the platform is "production ready." Despite overtaking Node, io.js clarifies the release in its own FAQ: "The choice to release as 1.0.x was not to signify that io.js should be considered production-ready, but because it was a significant enough release from Node.js to warrant a major version increment," it says.
The NodeJS based Koa web application framework has released version 0.2.0. Koa is the successor of the popular Express MVC platform, but relies heavily on newer ES6 constructs. This release is marked as an important one in that that it reaffirms the team’s design choices from the initial 0.1.0 release, solidifying Koa's API for future releases and production use.