React Native 0.82: The All-New Architecture Era – Q&A

React Native 0.82 marks a pivotal transition: it is the first version to run entirely on the New Architecture, leaving behind the legacy system. This release ushers in experimental Hermes V1, React 19.1.1, and DOM Node APIs, while simplifying the codebase for future growth. Below, we answer key questions about this milestone.

What makes React Native 0.82 a milestone release?

React Native 0.82 is the first version that only operates on the New Architecture. In previous versions (like 0.76), developers could toggle between legacy and new architectures. Now, attempts to set newArchEnabled=false on Android or RCT_NEW_ARCH_ENABLED=0 on iOS are ignored—your app will always use the New Architecture. This shift simplifies development, reduces bundle size in upcoming versions, and lays the groundwork for future improvements like removing legacy code entirely. Additionally, 0.82 includes an experimental opt-in for Hermes V1 (a more modern JavaScript engine), an update to React 19.1.1, and support for DOM Node APIs, making it a landmark release for the React Native ecosystem.

React Native 0.82: The All-New Architecture Era – Q&A

Why is the New Architecture now the only option?

Since becoming the default in React Native 0.76, the New Architecture has undergone extensive testing and refinement. The team is confident in its stability and performance, so locking it as the sole architecture streamlines the framework. This decision eliminates the need to maintain two parallel systems, reducing maintenance overhead and allowing the core team to focus on enhancing the New Architecture. Developers benefit from a more consistent experience, fewer compatibility issues, and access to new features like synchronous layout effects and better interop with React 19. While legacy architecture code is not yet removed in 0.82, future versions will begin stripping it away to further slim down the framework.

How can developers migrate to React Native 0.82 from older versions?

If you haven’t migrated to the New Architecture yet, start by updating to React Native 0.81 or Expo SDK 54—the last versions supporting the Legacy Architecture. These versions include warnings and performance improvements tailored for migration. Enable the New Architecture in 0.81 and verify your app works correctly. Once stable, you can safely upgrade to React Native 0.82. For third-party library incompatibilities, contact the library maintainers directly. If you encounter bugs in React Native core itself, report them via the issue tracker. The interop layers remain in the codebase for now, ensuring backward compatibility with libraries that support both architectures.

What is experimental Hermes V1 and how does it benefit developers?

Experimental Hermes V1 is an opt-in upgrade to the Hermes JavaScript engine, the default engine for React Native. While still experimental in 0.82, it offers potential improvements in startup time, memory usage, and debugging capabilities. Adopting Hermes V1 can lead to faster app launches and smoother performance, especially on lower-end devices. To enable it, developers can set specific flags during configuration. The React Native team plans to make Hermes V1 the default in a future release after gathering feedback. This forward-looking feature aligns with the goal of modernizing the engine to support the latest JavaScript features and optimize mobile app performance.

What changes come with React 19.1.1 and DOM Node APIs?

React Native 0.82 updates to React 19.1.1, bringing improvements in concurrent rendering, error handling, and hooks. More notably, it introduces DOM Node APIs, allowing developers to interact with native views using familiar DOM-like methods (e.g., getBoundingClientRect). This eases integration with web-oriented tools and libraries, reduces boilerplate, and makes it easier to write cross-platform code. While not a full DOM implementation, these APIs mark a significant step toward bridging web patterns with native performance. Combined with the New Architecture, these features empower developers to build richer, more responsive applications with less code.

Will third-party libraries and interop layers still work in 0.82?

Yes. The React Native team has committed to keeping interop layers in the codebase for the foreseeable future. All classes and functions required by these layers will remain available, ensuring that third-party libraries offering backward compatibility with both architectures continue to function seamlessly. The team has verified that libraries supporting both legacy and new architectures work without issues in 0.82. However, as the Legacy Architecture code is phased out in later versions, library maintainers are encouraged to update their code to rely solely on the New Architecture. Developers encountering problems with specific libraries should contact their maintainers directly.

When will the Legacy Architecture code be fully removed?

In React Native 0.82, none of the Legacy Architecture APIs or classes are removed—the focus is on ensuring a smooth transition. The actual removal is scheduled to begin in the next version (post-0.82), as outlined in RFC0929. This phased approach minimizes breaking changes and gives developers time to migrate. Removing the legacy code will significantly reduce the overall bundle size and simplify the codebase. The interop layers will remain until a later announcement. Developers are advised to complete their migration to the New Architecture now to avoid disruptions when the removal begins.

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