If you already have a React Native app in production, “React Native migration” probably means something different to you than it does to a team that has not touched React Native yet. This guide is about the second kind of migration: moving an existing React Native app from the old bridge-based architecture to the New Architecture, not rewriting a native iOS or Android app in React Native from scratch. If it is the framework decision itself you are still weighing, our React Native app development guide is the better starting point.
Meta stopped investing in the old bridge starting with React Native 0.80, released in June 2025, which means every app still running on the legacy architecture is now on borrowed time. This guide walks through what the New Architecture actually changes, a readiness checklist, the migration steps in order, a realistic timeline, and the mistakes that trip up most teams, so you can plan the upgrade with a clear head instead of guessing your way through it.
What Is React Native's New Architecture?
The New Architecture is not one feature. It rebuilds four core parts of React Native: TurboModules, the new way native modules load; Fabric, the new renderer; a rebuilt event loop; and the removal of the old asynchronous bridge in favor of a direct JavaScript-to-native interface called JSI. For a full breakdown of how these pieces fit together, see our article on how React Native's architecture works under the hood.
In practice, this shows up as faster app startup, fewer dropped frames during scrolling and animation, and fewer crashes caused by type mismatches between JavaScript and native code, since JSI checks types at the boundary instead of serializing everything into bridge messages first. The rest of this guide is narrower and more practical: how to move an existing app from the old architecture to this one without breaking production along the way.
Should You Migrate Now?
According to React Native's official engineering blog, the New Architecture became the default for every new app starting with React Native 0.76, released in October 2024. That alone would make migration worth planning. What pushes it closer to necessary is what happened afterward: Meta's 0.80 release in June 2025 froze further investment in the legacy architecture, so bug fixes, performance work, and new features stopped going into the old bridge.
If you are also reconsidering whether React Native is still the right framework for your app, that is a separate decision with its own tradeoffs, not something to fold into an architecture upgrade. Our comparisons on React Native vs Flutter and React Native vs a fully native rebuild are better starting points for that question. This guide assumes you are staying on React Native and simply need to move off the old bridge.
React Native Migration Timeline
A few version numbers explain most of the urgency in this guide. Here is how the New Architecture rollout has actually progressed:
Migration Readiness Checklist
Before you touch a single config file, confirm where you actually stand on each of these:
- Current React Native version
- Expo SDK version, if you are on Expo
- Third-party library compatibility, checked against reactnative.directory
- Custom Native Modules inventory
- Custom Native Components inventory
- Android build configuration (Gradle, NDK)
- iOS build configuration (CocoaPods, Xcodebuild)
- CI/CD pipeline compatibility
- Crash reporting and analytics SDK compatibility
Most teams assume app size predicts how hard this will be. It does not. Library and native module compatibility predicts it. A small app with two unmaintained native modules can take longer than a mid-size app built entirely on popular, well-maintained libraries.
How to Migrate Step by Step
Step 1: Update Your React Native Version
Start by checking exactly what changes between your current version and the one you are targeting, file by file, rather than upgrading blind. While this guide focuses on migration planning, compatibility checks, and implementation best practices, always cross-check version-specific commands and breaking changes against the official React Native upgrade documentation before touching a production app.
Step 2: Enable the New Architecture
On Android, this is a flag in gradle.properties:
newArchEnabled=true
On iOS, install pods with the New Architecture flag set:
RCT_NEW_ARCH_ENABLED=1 bundle exec pod install
Do this on a branch, not on main. The next few steps are where most of the actual work happens.
Step 3: Update Dependencies
Cross-check every third-party library your app actually uses against reactnative.directory before upgrading. Flag anything that still relies on the legacy bridge only and has no New Architecture support planned. This step, more than any other, determines your real timeline.
Step 4: Run Codegen
Codegen generates the type-safe native interface code from your JavaScript specs, which is what lets JSI catch type mismatches at the boundary instead of at runtime. You do not need to hand-write this layer. Run it, review the generated output for anything unexpected, and commit it alongside your code.
Step 5: Migrate Native Modules and Native Components
This is usually the slowest step, and the one where outside help pays off fastest if your team has not done a TurboModules migration before. If you need extra hands for this part specifically, it is worth talking to a team that has done this migration before rather than learning the TurboModule spec under a deadline. Our page on how to hire React Native developers walks through what to look for.
Step 6: Test Android and iOS Separately
New Architecture bugs surface differently per platform. Do not treat a passing Android build as a signal that iOS is fine, or the other way around. Run your full test suite on both, and manually test any screen that uses a custom native module or component.
Step 7: Validate Performance
Before you call the migration done, benchmark three things against your pre-migration baseline: cold start time, frame drops during list scrolling, and memory usage under normal use. If any of these got worse, it usually traces back to a library still running through the interop layer instead of natively on Fabric.
Common Migration Issues
Migration Risk Assessment
How risky your migration is depends far more on your native code footprint than on your app's feature count. If you are running a newer product with a small codebase, this whole process tends to be short; our notes on React Native for early-stage products cover why lean teams often have the easiest path here.
Time Estimation
These ranges assume a compatibility audit has already happened. If it has not, add time for that first. For a fuller picture of what a migration or upgrade project typically costs alongside developer time, see our breakdown of React Native app development cost.
Rollback Plan
Very few migration guides mention this, which is exactly why it gets skipped and then regretted. Keep the legacy architecture flag reachable during a transition window instead of deleting it the moment you flip to the new one. Roll the change out behind a staged release rather than to every user at once, and watch crash rates and performance metrics closely before you commit fully. If something regresses, you want a flag to flip back, not a git revert under pressure.
Post-Migration Checklist
- Android build verified on real devices, not just emulator
- iOS build verified on real devices, not just simulator
- CI pipeline updated for the New Architecture build flags
- Crash reporting confirmed working under the new setup
- Performance benchmarks compared against your pre-migration baseline
- Analytics events verified end to end
Final Thoughts
The New Architecture migration is rarely about difficulty. It is about sequencing: audit first, update dependencies before you flip the flag, and test both platforms separately instead of assuming a green Android build means iOS is fine too. Teams that treat this as a one-afternoon flag change are usually the ones who end up rolling it back. If you would rather hand this off to a team that has already run this migration on production apps, SpaceToTech's custom React Native app development services can take it from audit through to a validated release.
