It seems like apps by default fill one screen or the over in landscape mode, while by default they fill the whole screen in portrait, which is a nice setup that means that phone apps will mostly just work, which is nice. Some developers will customize how their interface works on the passport style ratio over the narrower design of current iPhone, like adding side controls, which will be nice, but not strictly necessary so smaller devs won’t need to do much. I do think the dominance of iPads really helps too compared to Android, as iOS users largely expect iOS apps to support phone, tablet, and laptop style use cases. So even when devs don’t do much to support the Duo, or take a long time to do so, work they’ve already done to support iPad screen sizes/ratios and the windowed multi-tasking setup on iPadOS will mean apps already handle some of the demands of the Duo, since even apps that generally prioritize phone use include the basics for iPad use.
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