ios – React Native 0.82.1 fails to construct on Xcode 26 with Yoga/fmt/glog C++ constexpr errors

I’m making an attempt to construct a React Native iOS app after upgrading to Xcode 26, however the construct fails throughout native compilation.

Surroundings

• React Native: 0.82.1

• React: 19.1.1

• Node: 20.19.6

• CocoaPods: newest

• Xcode: 26

• macOS Tahoe

Errors

The construct fails inside native dependencies resembling:

A few of the most important errors embrace:

constexpr operate by no means produces a relentless expression
name to consteval operate ... isn't a relentless expression

and failures from information like:

Pods/fmt/src/format.cc
ReactCommon/yoga/...
Pods/glog/src/...

The ultimate construct exits with:

xcodebuild exited with error code 65

What I already tried

• Cleansing Pods / DerivedData

• Reinstalling node_modules

• Working pod set up once more

• Disabling Hermes

• Disabling Cloth / New Structure

• Forcing gnu++17

• Including customized OTHER_CPLUSPLUSFLAGS

Nonetheless, React Native 0.82 appears to drive components of the New Structure internally, so disabling it doesn’t totally work anymore.

Podfile modifications tried

config.build_settings['CLANG_CXX_LANGUAGE_STANDARD'] = 'gnu++17'

and:

:hermes_enabled => false

Query

Has anybody efficiently constructed React Native 0.82.x on Xcode 26?

Is that this presently a recognized compatibility difficulty between RN 0.82 and the Xcode 26 toolchain, or is there a secure workaround moreover downgrading Xcode?