Expo SDK 55 Released with React 19.2 Support, Defaults to New Architecture
Expo has released SDK 55, a major update for the React Native framework that drops legacy architecture and makes the New Architecture the default. The release includes support for React 19.2 and React Native Router v7. It also introduces new AI tooling, such as MCP for Claude Code, and features Hermes diffing for up to 75% smaller over-the-air updates.
- With the legacy architecture removed, SDK 55 requires React Native 0.83.1, which in turn brings support for React 19.2. This version of React introduces a new `<Activity>` component for UI prioritization and a `useEffectEvent` hook for better management of effects. - The new default project template now includes a `/src/app` directory to better separate application logic from root configuration files. It also uses a native tabs API for a more authentic platform tab experience on both iOS and Android. - Integration with existing native applications, a "brownfield" approach, is now streamlined with a new `expo-brownfield` package. This allows React Native code to be packaged as a native library (AAR for Android, XCFramework for iOS), which native development teams can consume without needing to set up a Node.js environment. - The AI tooling, MCP (Model Context Protocol) for Claude Code, allows AI agents to interact directly with Expo projects. This enables the AI to run builds, diagnose errors, modify configurations, and access the latest official Expo documentation on demand. - To clarify version compatibility, all Expo packages now share the same major version as the SDK. For instance, with SDK 55, the `expo-camera` package is now version `^55.0.0`. - The Hermes bytecode diffing for over-the-air (OTA) updates is an opt-in feature in SDK 55 and is planned to be enabled by default in SDK 56. This feature sends only the binary patch between updates, which can significantly speed up the process for users. - React Native Router v7 is a non-breaking upgrade from v6 that offers improved type safety for route parameters and loader data. It also enhances data loading capabilities with `loader` functions that execute before a route component renders. - Support for home screen widgets and Live Activities on iOS is now available in alpha through `expo-widgets`. This allows developers to build these native UI features using familiar Expo and React Native components without writing Swift code directly.
