SDK 55 beta is now available for developers, running for about two weeks. This beta phase allows developers to test the new SDK and check for regressions in their applications. It includes React Native 0.83.1 and React 19.2.0. Key changes include the removal of Legacy Architecture support, meaning projects must adopt the new architecture moving forward. The default project template has been revamped to better align with native platform conventions, introducing a new folder structure for project files and application code. Hermes v1 is now an optional feature, promising performance improvements and better support for modern JavaScript. However, using Hermes v1 requires building React Native from source, which could lengthen native build times. Developers can also take advantage of Hermes bytecode diffing, a feature that reduces update download sizes significantly, potentially cutting download times by around 75% on both Android and iOS. The update brings enhancements to Expo Router, including a new Colors API for adaptive styles, support for interactive shared element transitions on iOS, and an improved Stack.Toolbar API for iOS apps. The SDK also strengthens support for integrating Expo with existing native applications through the new expo-brownfield package, allowing developers to package React Native code as a native library for easier integration. These changes reflect Expo's ongoing commitment to improving developer experience and app performance.