With iPhone Duo, are size classes deprecated?
Asked on 2026-10-29
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No — based on the WWDC context, size classes are not deprecated.
In fact, the guidance in Modernize your UIKit app says to use size classes for sizing decisions and to stop using user interface idiom or interface orientation for layout logic. The newer direction is:
- Don’t rely on idiom for layout decisions
- Don’t rely on interface orientation for layout decisions
- Do use size classes for adapting layout to available space
So for “iPhone Duo” / resizable iPhone environments, the message is that apps should adapt with size classes, not that size classes themselves are deprecated.
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