It appears that over the past few days that Angular 4.x (RTM) was released.
Interestingly, I was digging around to see if there is anything needed to edit in order to target the newer versions and found that my plunks that were targeting 2.x automagically work with and target 4.x.
One way to see this is to view the source of and you can note the version in the “ng-version” attribute that gets injected into your mark-up.
For my plunks, I immediately saw this attribute on the primary “app” component that is bootstrapped, for example:
It’s good to know that my prior plunks work as-is without modifications!
The release notes can be found here: https://angular.io/docs/ts/latest/