At the time of writing, Vue.js 2.0 was announced ( https://vuejs.org/2016/04/27/announcing-2.0/ ). Check the following links in this regard:
The second version of Vue.js has some considerable differences comparing to its predecessor, starting from the way that data binding is being handled and moving to its API. It uses lightweight virtual DOM implementation for rendering, supports server-side rendering, and is faster and leaner.
At the time of writing, Vue 2.0 was in an early alpha stage. Do not worry, though. All the examples that we will cover in this book are based on the latest stable version of Vue 2.0 and are fully compatible with the both the versions.