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npm / @react-native/metro-config

@react-native/metro-config

What changed in @react-native/metro-config 0.83 to 0.88, from its official release notes, upgrade guides and advisories. Also covers @react-native/babel-plugin-codegen, @react-native/dev-middleware. Sources checked 2026-10-18.

4 breaking3 new APIs and options1 performance2 behavior and defaults7 tooling16 fixes and other

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@react-native/metro-config 0.884 changes

Breaking changes 1

  • When the desktop app fails to launch, the fallback opens DevTools as a standard window in the default browser instead of attempting Microsoft Edge.

    0.88.0release notes

New APIs and options 1

  • Users and agents can capture app screenshots with this command; experimental performance screenshot support is also available in the EXPERIMENTAL channel.

    0.88.0release notes

Tooling 1

  • WebSocket event inspection is available in the Network panel in the CANARY channel.

    0.88.0release notes

Fixes and other changes 1

  • Dev server WebSockets no longer throttle bundle downloads or other dev server requests.

    0.88.0release notes

@react-native/metro-config 0.877 changes

Breaking changes 1

  • Support for connecting to the standalone react-devtools package via WebSocket is removed; use React Native DevTools instead.

    0.87.0release notes

Performance 1

  • Memory usage during JS bundle downloads is reduced by eliminating intermediate buffer copies.

    0.87.0release notes

Tooling 4

  • New options are exposed in the React Native DevTools app menu.

    0.87.0release notes

  • React Native DevTools now shows request body previews for FormData and file uploads.

    0.87.0release notes

  • The modern inspector implements this CDP method, allowing scripts to be added for evaluation on new documents.

    0.87.0release notes

  • The modern inspector implements this CDP method for removing scripts registered for evaluation on new documents.

    0.87.0release notes

Fixes and other changes 1

  • React Native DevTools no longer briefly flashes in the system dock or taskbar when Metro starts.

    0.87.0release notes

@react-native/metro-config 0.8612 changes

New APIs and options 1

  • Dev-mode Metro bundle loads now call methods on this global when it is provided, allowing a bundle loader reporter to observe loads.

    0.86.0release notes

Tooling 2

  • React Native DevTools supports light and dark mode emulation through this method.

    0.86.0release notes

  • Performance traces in React Native DevTools include a custom track for React Native Renderer operations.

    0.86.0release notes

Fixes and other changes 9

  • Fixes a use-after-free data race in EventEmitter.cpp.

    0.86.3release notes

  • Custom fonts with an explicit fontWeight no longer render at the heaviest weight on the New Architecture.

    0.86.3release notes

  • Fixes a ConcurrentModificationException when getInitialURL re-enters during onHostResume.

    0.86.3release notes

  • For Modal and other nested root host views, parentNode and parentElement now return the containing element instead of the document, preserving capture and bubble event propagation to ancestors.

    0.86.3release notes

  • SPEC CHECKSUMS are deterministic across machines by sorting Yoga.podspec glob results and using a dynamically computed Pods-relative path in hermes-engine.podspec.

    0.86.3release notes

  • React DevTools connections derive their WebSocket scheme and port from the dev server URL, supporting HTTPS dev servers.

    0.86.0release notes

  • Fixed inspector server host resolution for HTTPS bundle URLs by omitting the default port.

    0.86.0release notes

  • The reconnect loop now uses exponential backoff and handles exceptions to prevent heap fragmentation crashes.

    0.86.0release notes

  • Fixed iOS dev-support IPv6 handling for packager and inspector connections.

    0.86.0release notes

@react-native/metro-config 0.858 changes

Breaking changes 2

  • The debugger proxy now permits connections only from localhost.

    0.85.0release notes

  • Page targets returned from /json/list no longer set prefersFuseboxFrontend.

    0.85.0release notes

New APIs and options 1

  • React Native DevTools now supports multiple CDP connections to one React Native Host.

    0.85.0release notes

Behavior and default changes 2

  • LogBox warnings and errors are suppressed during CDP performance tracing.

    0.85.0release notes

  • serverBaseUrl now accepts either a string or a URL.

    0.85.0release notes

Fixes and other changes 3

  • Fixes the banner getting stuck after reloads in quick succession on iOS.

    0.83.6, 0.85.2release notesrelease notes

  • React Native DevTools can reach Metro from the debugger at URLs other than localhost:8081 and 127.0.0.1:8081.

    0.85.0release notes

  • Network events are sent to all CDP clients that have the Network domain enabled.

    0.85.0release notes

@react-native/metro-config 0.832 changes

Fixes and other changes 2

  • Fixes incorrect multi-host detection for apps using additional Hermes runtimes, such as Reanimated.

    0.83.10release notes

  • Limits the WebSocket queue size to prevent the Android inspector from being force-disconnected on large payloads.

    0.83.10release notes