What iOS and Android versions will Ionic2 support?

Does anyone know what versions of iOS and Android Ionic2 support?

I just tested my app on Android 4.1 and Android 4.2, and the flexbox layout styles do not work. I’m wondering if this is a short-term thing, or will they be sticking with these styles long-term?

Can’t say about iOS, but for Android have a look here: http://blog.ionic.io/crosswalk-comes-to-ionic/

Ionic/Cordova apps run on a webview. If I’m not wrong Android prior to 4.3 uses an outdated webview and that’s why some styles won’t work, and also the performance won’t be optimal. By using crosswalk you make sure your app will run on the desired webview therefore its behaviour will be the same in any Android version (although I’m not sure about versions prior to 4).