iPhone Duo

Help the existing app work across changing containers, then adopt device capabilities where the requested experience benefits. Preserve the app's framework, architecture, minimum OS support, and feature scope unless the user asks to change them.

Establish the evidence boundary

Read support and migration before making availability or compatibility claims. This skill records research from 2026-09-15, including announced iOS 27.1 features whose reference pages and SDK were not available for validation in that research environment.

• Distinguish build SDK, deployment target, runtime version, and hardware capability.
• Prefer current Apple declarations and release notes for exact availability; use Apple HIG for design intent and sessions for announced behavior.
• If Cupertino MCP is available, search and read its documents. Missing search results can mean a stale index: use the official source links rather than guessing or declaring the API nonexistent.
• Confirm exact declarations before emitting new-API implementation code. An if #available condition cannot make an unknown symbol compile against an older SDK.
• Without a suitable SDK/runtime, implement verified adaptive improvements and report the remaining device-specific validation separately.

Choose the relevant references