Angular 2 is at RC4 with only one RC version currently planed before the official release, as seen from their active milestones, but I haven't heard any information on a official release date yet.
Every new release of Angular introduce some breaking changes - some noticeable, some not, so you should keep an eye on the Angular Changelog every now and then.
The long-term goal for Angular is to make the framework "future-proof" and every update stress-free. There are some plans for upgrade scripts to make this happen (Angular 1 to Angular 2 Upgrade Strategy and Upgrading from 1.X for more detailed information).
I've seen several production ready Angular 2 apps shipped with very positive feedback from the developers. The latest releases are stable enough to be used in production, so more and more companies are adopting it for their small to medium projects.
That being said, you should take the cons and pros of using Angular 2 today and consider the tradeoffs - how will this affect your development and productivity and will you be able to deliver the user experience and features on time and with ease.