Spotify Web 1.57 - Adaptive / Classic style switch for the app icons (Android 8+)

Adds an Adaptive | Classic switch to the App icon dialog on Android 8+, so every palette can be used in two styles.

Adaptive is the modern icon your launcher shapes, with the themed monochrome version. Classic is the round icon with a thin ring, as on Android 7, redrawn as a sharp vector.

The picker opens on your current style. The switch only changes which list you are looking at, and tapping an icon row applies that palette in the shown style.

Classic has no themed (monochrome) version. Some launchers draw it on their own white backplate instead of showing the bare circle, which the app can't change.

Android 7 has no switch, since adaptive icons aren't supported there. Its old low-resolution fallback PNG icon files are also replaced with the same Classic vector, so the icon is sharp on every screen.