#OTA updates for the React Native New Architecture

React Native 0.82 is the first release that runs only on the New Architecture: setting newArchEnabled to false has no effect any more. Every OTA update library you depend on now has to work with TurboModules and bridgeless mode.

That rules out react-native-code-push. Its archived README states that CodePush won't support the New Architecture, so apps that still use it are stuck on React Native 0.81 or earlier. This guide covers what changes for OTA updates on the New Architecture and how to set them up with Cresc.

#What the New Architecture changes for OTA updates

An OTA library does two things natively: it tells React Native which JS bundle to load at startup, and it exposes a native module that JS calls to check, download and apply updates. The New Architecture touches both.

• Native modules become TurboModules. Modules are described by a typed spec and generated with codegen, then loaded through TurboModuleRegistry instead of NativeModules. A library without a TurboModule spec only works through interop layers, if at all.
• Bridgeless mode removes the bridge. There is no RCTBridge to hand a bundle URL to and no bridge to reload. Libraries that read or reset the bundle through the bridge break.
• The bundle URL moved. On Android, React Native 0.82+ templates create a ReactHost with getDefaultReactHost(...) instead of overriding getJSBundleFile() on a ReactNativeHost. On iOS, React Native 0.88 templates moved the entry point and bundleURL() from AppDelegate to SceneDelegate.
• Hermes is the default engine. Bundles ship as Hermes bytecode, and plain binary diffs of bytecode are much larger than diffs of JavaScript text.

#How Cresc supports it

The Cresc SDK, react-native-update, has supported the New Architecture since v9.0.0 (2023) and builds for both architectures from the same code:

• A codegen TurboModule spec (codegenConfig named RCTPushySpec). Android uses a TurboReactPackage and iOS implements getTurboModule: when the New Architecture is on.
• Bridgeless detection at runtime. The JS side picks the TurboModule when __turboModuleProxy or RN$Bridgeless is present and falls back to NativeModules on the legacy architecture. There is nothing to configure.
• Bundle URL helpers for each template: UpdateContext.getBundleUrl(context) on Android and RCTPushy.bundleURL() on iOS, plus native host APIs (prepareBundle) for apps that create the React host themselves.
• Hermes-aware diffs. The CLI transforms Hermes bytecode before diffing, which removes the offset shifts that inflate binary patches. In an open benchmark on React Native 0.86, a one-line change shipped as 3.4 KB, against 93.7 KB with plain bsdiff and 1.5 MB as a full bundle.

One known limitation: on Android, React Native 0.73.0 to 0.76.0 has an upstream bug that breaks the New Architecture for this SDK. Versions below 0.73, and 0.76.1 and later, work.

#Setup on the New Architecture

The full steps, including Expo and older templates, are in Installation & Config. The two native changes are:

#Android (React Native 0.82 and later)

Pass Cresc's bundle path to getDefaultReactHost in MainApplication.kt:

import cn.reactnative.modules.update.UpdateContext

class MainApplication : Application(), ReactApplication {

  override val reactHost: ReactHost by lazy {
    getDefaultReactHost(
      context = applicationContext,
      packageList = PackageList(this).packages,
      jsBundleFilePath = UpdateContext.getBundleUrl(this),
    )
  }
}

On React Native 0.81 and earlier, return UpdateContext.getBundleUrl(...) from getJSBundleFile() instead.

#iOS (React Native 0.88 and later)

Return Cresc's bundle URL from bundleURL() in SceneDelegate.swift, keeping Metro for debug builds:

import react_native_update

class SceneDelegate: RCTDefaultReactNativeFactoryDelegate, UIWindowSceneDelegate {
  override func bundleURL() -> URL? {
    #if DEBUG
    RCTBundleURLProvider.sharedSettings().jsBundleURL(forBundleRoot: "index")
    #else
    RCTPushy.bundleURL()
    #endif
  }
}

On React Native 0.87 and earlier the same method lives in AppDelegate. When you follow the Upgrade Helper to 0.88 and move the entry point to SceneDelegate, move RCTPushy.bundleURL() with it. Otherwise release builds keep loading the embedded bundle and updates never apply.

#Expo

With Expo SDK 50 and later, run npx expo prebuild and the bundle URL is configured automatically on both platforms. Don't install expo-updates alongside Cresc.

#Brownfield and custom hosts

If React Native is embedded in a native app, packaged as an AAR, or the host creates its own ReactHost, see Brownfield Integration and the native prepareBundle APIs in Native Configuration and Updates.

#Upgrading from CodePush to React Native 0.82+

1. Replace react-native-code-push with react-native-update while still on your current React Native version, and ship one store release with it. The API migration guide maps every CodePush call.
2. Upgrade React Native. With CodePush gone, nothing blocks the New Architecture.
3. After any native upgrade, upload the new native package to Cresc before publishing OTA updates against it (Publishing).

#FAQ

#Does CodePush work with the React Native New Architecture?

No. The archived react-native-code-push README states it won't support the New Architecture, and React Native 0.82 and later no longer allow opting out. Apps on CodePush can't upgrade past React Native 0.81 without replacing it.

#Does Cresc support bridgeless mode?

Yes. react-native-update detects bridgeless mode at runtime and uses its TurboModule; the same package still works on the legacy architecture.

#Which React Native versions does Cresc support?

Both architectures, from older legacy-architecture apps through current releases including React Native 0.88. On Android, the New Architecture on React Native 0.73.0 to 0.76.0 is affected by an upstream bug; use 0.76.1 or later.

#Do OTA updates work with Hermes bytecode?

Yes. Cresc publishes Hermes bytecode bundles and diffs them with a Hermes-aware transform, so small changes produce patches of a few KB.

#Related

• App Center and CodePush retirement guide
• Installation & Config
• Brownfield Integration
• React Native OTA updates with Cresc
• HarmonyOS