iPhone Duo design and readiness

Help an app keep its identity and functionality while its usable space changes. This skill works with any coding assistant that can read Markdown. Shell, browser, Xcode, and simulator tools are optional capabilities, not host-specific dependencies. When a tool is unavailable, provide the exact remaining check and keep its result unverified.

Establish the target

Before changing code, inspect the app's deployment targets, Swift language mode, selected Xcode/SDK, UI framework, scene configuration, and principal user flows. For design-only work, record any unknowns instead of choosing a deployment target for the user. Preserve existing platform support unless the user requests a change.

Read versions and sources before proposing Duo-specific symbols. Refresh the official sources when implementation depends on their current availability. The source snapshot is dated September 17, 2026; it is not a claim about the SDK available in a future session.