React Native 0.84: 8 Major Updates That Transform Your Development Experience

React Native 0.84 has arrived, bringing a wave of changes that make your apps faster, your builds shorter, and your codebase cleaner. This release makes Hermes V1 the default JavaScript engine, ships precompiled iOS binaries, continues removing legacy architecture, and raises the Node.js minimum to 22. Whether you're a seasoned developer or new to React Native, these updates will reshape how you build and maintain mobile apps. Here are the eight most important things you need to know.

1. Hermes V1 Is Now the Default JavaScript Engine

After an experimental opt-in period in React Native 0.82, Hermes V1 becomes the default JavaScript engine for both iOS and Android with version 0.84. This next-generation engine builds on the Hermes compiler and virtual machine with major enhancements. The result is measurably better execution speed and lower memory usage—all without any extra work on your part. If you've been using Hermes (the default since 0.70), your app will automatically upgrade to V1. This change alone can boost performance significantly, especially for complex UIs and animations.

2. Automatic Performance Gains Without Code Changes

Because Hermes V1 is now the default, every React Native 0.84 app gets a free performance boost. The engine's improved JIT compilation and garbage collection reduce startup time and runtime overhead. For example, list scrolling becomes smoother, and memory-intensive operations like image loading use fewer resources. You don't need to modify a single line of code—the gains happen under the hood. This is a huge win for existing projects that upgrade to 0.84: they immediately benefit from faster initial render and reduced jank.

3. No Migration Required for Current Hermes Users

If your project already uses Hermes (standard since React Native 0.70), upgrading to 0.84 seamlessly switches you to Hermes V1. There are no configuration changes needed in your metro.config.js, babel.config.js, or any other files. The package manager (npm, yarn, or pnpm) automatically pulls the new Hermes version. For teams that have been hesitant to adopt Hermes because of past migration concerns, this release eliminates that barrier. You get all the performance benefits with zero migration overhead.

4. How to Opt Out of Hermes V1 (If You Really Need To)

While Hermes V1 is the default, you can opt out if you have a specific reason—like compatibility with a legacy library. For package manager overrides, use hermes-compiler: 0.15.0 in your package.json under overrides (npm), resolutions (yarn), or pnpm.overrides. On iOS, set RCT_HERMES_V1_ENABLED=0 and RCT_USE_PREBUILT_RNCORE=0 during pod install. On Android, add hermesV1Enabled=false to android/gradle.properties and build from source. These steps force the legacy Hermes version, but be aware you'll miss out on the performance improvements.

5. Precompiled iOS Binaries Reduce Build Times

React Native 0.84 ships precompiled iOS binaries (.xcframework) by default, a change that was opt-in in previous versions. Now, when you run pod install, the core framework binaries are downloaded instead of compiled from source. This cuts clean build times dramatically—sometimes by several minutes—especially on CI or large teams. No more waiting for React-Core to recompile every time. If you need to build from source (for example, to opt out of Hermes V1), set RCT_USE_PREBUILT_RNCORE=0 during pod installation.

6. Legacy Architecture Code Continues to Be Removed

Building on the New Architecture transition started in 0.82, 0.84 removes even more legacy code from both iOS and Android. On iOS, the experimental RCT_REMOVE_LEGACY_ARCH flag—introduced in 0.83—is now enabled by default. This compiles out legacy components, reducing both app bundle size and build time. The Android side also sees further pruning of the old architecture. If your app is already on the New Architecture, you won't notice any breakage—only a leaner codebase. This cleanup paves the way for future optimizations and a fully unified architecture.

7. Node.js 22 Is Now the Minimum Requirement

React Native 0.84 bumps the minimum Node.js version from 18 to 22. This aligns with newer language features used by the toolchain and the Hermes V1 compiler. While this may require updating your development environment or CI containers, Node.js 22 brings performance improvements and better ES module support. Most developers already using Node 20 should upgrade to 22 to ensure compatibility. The change is straightforward—just update your package.json engines field or your Docker images. Legacy Node versions will not work with this release.

8. What These Changes Mean for Your Development Workflow

Together, these updates streamline your React Native experience. With Hermes V1 default, you get faster apps out of the box. Precompiled binaries slash iOS build times. Removing legacy code reduces bloat and potential bugs. And the Node.js requirement ensures you're using a modern runtime. There's no urgent migration—just upgrade your project to 0.84, and most improvements are automatic. For advanced users, opt-out paths preserve backward compatibility. This release signals React Native's commitment to performance and developer productivity without introducing breaking changes for the majority of apps.

In summary, React Native 0.84 is a powerhouse update that enhances performance, reduces build overhead, and cleans up technical debt. Whether you're building a new app or maintaining an existing one, upgrading is a no-brainer. The future of React Native is leaner, faster, and more developer-friendly—starting with version 0.84.