Sorry, late to the game. In 2025, is this the way? MKCircle says it's not meant to be subclassed, but doesn't specifically say it will break things. I got a subclass of MKCircle working fine when calling a "convenience" initializer of MKCircle. Ditto MKPolyline. But not MKMultiPolyLine. It crashes with unrecognized selector sent to [ points], once subclassed, even when initialized with its primary initializers, and a var member set externally.

Same here. Thanks - could you expand on your solution, I don't follow? I've tried putting the @available at the root of var body, I tried using a ViewModifier, but still I get the same crash on 14.x.