[dlubarov]

I don't really see a difference. Android's API changes are almost always backwards compatible. There are a few exceptions, like AudioManager.setRouting (now a no-op), but they're very rare. For the most part, apps built for for early versions of Android still work fine on modern devices.

The support libraries which the parent referred to are optional utilities. They're often the most convenient way to implement something like a snackbar (https://material.io/guidelines/components/snackbars-toasts.h...), but they're by no means required. Just like on the Windows side, WPF is probably the most convenient way to create a ribbon, but you could build your own with the old win32 APIs if you wanted to, or just not use ribbons.