Missing official guide for safe migration of iOS projects from Objective-C to Swift

[coldSeattle]

Missing official guide for safe migration of iOS projects from Objective-C to Swift

Description

Many React Native apps that were created before RN 0.77 still use Objective-C in the iOS folder (AppDelegate, native modules, etc.).

Starting from RN 0.77+, the default iOS template switched to Swift with RCTAppDelegate, and RN 0.79 introduces Swift-friendly module registration via ios.modulesProvider.

However, there is no official documentation or migration guide that explains:

1. Whether developers should migrate their existing Obj-C iOS projects to Swift at all – is it optional, recommended for future compatibility, or required in upcoming releases?
2. How to do this migration safely, for example:
   • Converting AppDelegate from Obj-C to Swift (using RCTAppDelegate)
   • Handling projects that have a mix of Obj-C + Swift code (bridging-header best practices)
   • Migrating existing native modules (written in Obj-C) to the new Swift-friendly registration
   • Potential pitfalls with Pods, Xcode targets, build settings, deployment targets
3. Expected benefits vs. risks of migrating – maintenance, future upgrades, new architecture support.

At the moment, developers have to rely on Upgrade Helper diffs and community blog posts, which don’t provide a safe, step-by-step path for this transition.

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Request

It would be extremely helpful if the React Native team could:

• 📘 Publish an official migration guide in the docs or blog for transitioning iOS projects from Obj-C to Swift.
• ❓ Clarify if / when Obj-C support might be deprecated so teams can plan accordingly.
• 💻 Provide sample code or templates for common scenarios:
  • Swift AppDelegate using RCTAppDelegate
  • Mixed Obj-C / Swift native modules
  • Bridging-header setup
• ⚠️ Highlight known pitfalls (Pods, build settings, deployment target changes).

Such guidance would save teams significant effort and reduce the risk of breaking changes during upgrades.

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Environment

• Current project: React Native 0.78 (iOS folder mostly Obj-C)
• Target upgrade: React Native 0.79 (with Swift-friendly modules)
• Xcode 15+, iOS 15+ deployment target
• Project contains custom native modules written in Obj-C and plans to adopt Swift going forward.

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Motivation

Upgrading from 0.78 → 0.79 leaves developers without a clear path for migrating the iOS folder to Swift.
An official guide would clarify whether migration is necessary, how to do it safely, and what benefits it brings.