React Native: Legacy Architecture Cleanup

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Good morning. This is your React Native briefing for June 4th, 2026.

The dominant pattern today is aggressive legacy architecture cleanup, with multiple breaking changes removing deprecated APIs and build configurations. This signals React Native's push toward full new architecture adoption.

The iOS cleanup was comprehensive. PR 57069 removed deprecated legacy architecture protocol APIs, while PR 57065 eliminated unused bridge-based TurboModule manager initializers. PR 57067 stripped RCTBridge methods from the React Native Factory protocol entirely. These aren't minor housekeeping changes - they're breaking API removals that will force developers to update their integration code. The team also gated legacy view manager interop behind a compile flag in PR 57071, allowing apps that have fully migrated to Fabric to eliminate this compatibility layer entirely.

Platform capabilities saw important enhancements. PR 57062 added ArrayBuffer support to Java TurboModules, completing the cross-platform ArrayBuffer story that began with C++ and Objective-C implementations. This enables zero-copy buffer operations in Java, which should improve performance for data-intensive applications. Meanwhile, PR 57074 fixed a critical Android Fabric event coalescing bug where custom coalescing keys were being dropped, causing incorrect event replacement before JavaScript received them.

Additional commits included promoting event loop control interfaces out of unstable status and implementing CSS Flexbox automatic minimum sizing as an opt-in feature through Yoga configuration.

What's next: Developers using legacy architecture APIs need to audit their code against these breaking changes. The legacy interop gating suggests more aggressive deprecation timelines ahead. The ArrayBuffer and event coalescing fixes should improve reliability for production apps immediately.

That's your React Native update. Back tomorrow.