[iOS] React Native 0.83.1 fails to build with Xcode 26.0 - "Could not build module" errors

[arunbringmeal1125]

Issue Summary

React Native 0.83.1 fails to build on Xcode 26.0 (stable release) with multiple "Could not build module" errors, despite following all recommended upgrade steps and workarounds.

Environment

• React Native: 0.83.1
• Xcode: 26.0 (Build 17A324) - stable release, NOT beta
• macOS: 15.2 (Sequoia)
• Mac: M2 Mac mini 2023 (Apple Silicon)
• Target Device: iPhone (real device)
• Node: 23.10.0
• npm: 10.9.2
• CocoaPods: 1.16.2

Build Errors

Build fails in React-RuntimeHermes with the following module errors:

❌ Could not build module 'UIKit'
❌ Could not build module '_DarwinFoundation1'
❌ Could not build module 'CoreFoundation'  
❌ Could not build module '_Builtin_stdbool'
❌ Could not build module '_AvailabilityInternal'
❌ Could not build module 'Foundation'

Steps Taken

Upgrade Path:

1. Upgraded from React Native 0.76.6 → 0.83.1
2. Updated package.json:

   "react-native": "0.83.1"
   "react": "19.0.0"

3. Ran npm install
4. Updated iOS Podfile for RN 0.83.1
5. Ran pod install - completed successfully (90 dependencies)

Troubleshooting Attempts:

✅ Complete clean reinstall:

• Deleted node_modules, ios/Pods, ios/Podfile.lock, ios/build
• Cleared ~/Library/Developer/Xcode/DerivedData/*
• Fresh npm install and pod install

✅ Added Firebase compatibility:

• Added use_modular_headers! to Podfile
• Set $RNFirebaseAsStaticFramework = true

✅ Xcode 26 compatibility workaround:

• Set SWIFT_ENABLE_EXPLICIT_MODULES = 'NO' in post_install
• Set IPHONEOS_DEPLOYMENT_TARGET = '15.1'

✅ Disabled New Architecture:

   use_react_native!(
     :hermes_enabled => true,
     :fabric_enabled => false,
     :new_arch_enabled => false
   )

❌ Build still fails with the same module errors

Current Podfile Configuration

platform :ios, '15.1'
prepare_react_native_project!

use_modular_headers!

target 'Project' do
  config = use_native_modules!

  use_react_native!(
    :path => config[:reactNativePath],
    :app_path => "#{Pod::Config.instance.installation_root}/..",
    :hermes_enabled => true,
    :fabric_enabled => false,
    :new_arch_enabled => false
  )

  post_install do |installer|
    react_native_post_install(
      installer,
      config[:reactNativePath],
      :mac_catalyst_enabled => false
    )
    
    installer.pods_project.targets.each do |target|
      target.build_configurations.each do |config|
        config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '15.1'
        config.build_settings['SWIFT_ENABLE_EXPLICIT_MODULES'] = 'NO'
      end
    end
  end
end

Workaround That Works

Downgrading to Xcode 16.2 resolves all build errors ✅

• Same RN 0.83.1 codebase
• Same Podfile configuration
• Builds successfully without any errors

Questions

1. Is this a known incompatibility between React Native 0.83.1 and Xcode 26.0 stable?
2. Is there a fix planned for RN 0.83.x or should we wait for 0.84/0.85?
3. ETA on official Xcode 26 support? Apple requires Xcode 26 SDK for App Store submissions starting April 2026

Related Issues

• Similar issue reported: "could not build module" errors on Xcode 16.2, react native 0.76.6 facebook/react-native#49347
• But that issue uses RN 0.76.6 - I'm on 0.83.1 and still experiencing this

Additional Context

This affects the ability to prepare apps for App Store submission after April 2026. Many React Native developers will need Xcode 26 compatibility soon.

Any guidance or timeline for official support would be greatly appreciated!

[tsapeta]

I'm not sure what's the cause here, but Xcode 26.0 is supported in RN 0.83 since the beginning. Is this an Expo project? I guess regenerating the ios folder might help as a lot of things has changed there since 0.76.