AppGyver dev here! The core of Supersonic is framework-independent, so we're not at a risk of becoming stuck with an old version. We're monitoring AngularJS 2.0 closely, and will bring all relevant components up-to-date when the time comes to switch over (or we'll keep providing legacy support if that seems like its required).

As an example: unlike e.g. Ionic, our navigation is not built on top of AngularJS, but leverages the native navigation stack instead. Angular can be used to enhance the core Supersonic bits (as we do in many places), but it's not a lock-in.