Xcode 27 introduces enhanced test framework interoperability modes (Limited, Complete, Strict) that control how cross-framework issues are reported when mixing XCTest and Swift Testing in the same target, making it safer and more structured to incrementally migrate from XCTest to Swift Testing.
ā¢ New interoperability modes (Limited, Complete, Strict, None) added in Xcode 27 ā previously there was no graduated control over cross-framework issue severity
ā¢ Complete mode is now the default for new Xcode 27 projects, elevating cross-framework issues from warnings to errors
ā¢ SPM gains equivalent mode support via swift-tools-version 6.4 and an environment variable override
ā¢ `Test.cancel()` and `sourceLocation` parameter on `Issue.record` are now the canonical replacements for `XCTSkip` and `XCTFail(file:line:)` respectively
ā¢ Three configurable interoperability modes (Limited, Complete, Strict) let teams control the severity of cross-framework issue reporting, enabling a gradual, low-risk migration path
ā¢ Complete mode (default for new Xcode 27 projects) elevates cross-framework issues to errors, ensuring mixed-framework tests don't silently hide bugs
ā¢ Strict mode causes a fatal error at the exact call site where XCTest API is used inside a Swift Testing test, making it trivial to pinpoint and replace legacy assertions
iOS 27 adds sectioned queries, codable model attributes, ResultsObserver for non-SwiftUI change observation, and HistoryObserver for reacting to persistent history changes in SwiftData.
iOS 27 expands the App Intents framework with RelevantEntities for contextual content surfacing, EntityCollection for high-performance batch parameter handling, SyncableEntity for cross-device Siri continuity, native Duration/PersonNameComponents parameter types, and @UnionValue for multi-type parameters ā plus extended intent execution time limits.
USDKit is a new first-party Swift framework introduced in iOS/macOS 27 that brings native USD scene creation, composition, modification, and export capabilities to Apple platform apps, with deep RealityKit and Spatial Preview integration.
In-depth guide
iOS 26 ā iOS 27 Migration Guide āXcode 27 introduces an agentic localization workflow that lets you ask a coding agent to translate your entire app directly inside Xcode, leveraging String Catalog context ā including where and how strings are used ā to produce accurate, consistent translations across all languages.