iOS 27 adds language-aware delivery to Managed Background Assets, allowing the system to download only the asset packs that match a player's preferred language setting. This reduces on-device storage and download size for games with multilingual content.
• iOS 27 adds localized asset packs: the system now reads the user's preferred language from Settings and delivers only the matching language asset packs.
• Automatic fallback chain introduced: regional variant → base language → primary app language.
• New xcrun ba-package convert CLI tool converts Steam depot manifests into Background Assets–compatible asset pack archives.
• New Apple Unity plug-ins for Background Assets and StoreKit are now available, bridging the native frameworks to a C# API for Unity game developers.
• Players only download assets for their chosen language — dramatically reducing storage footprint for games with audio, video, or text in multiple languages.
• Automatic language fallback (regional → base language → primary app language) means developers don't need to handle edge cases manually.
• A new xcrun ba-package convert tool can convert Steam depot manifests directly into Apple asset pack archives, significantly lowering the barrier for cross-platform game developers.
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 — 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 → iOS 27 Migration Guide →Xcode 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 — including where and how strings are used — to produce accurate, consistent translations across all languages.