16.3 — Expo Changelog

APR 1, 2025

We have released patches for four modules to address a breaking change in Xcode 16.3, which was released March 31st. The breaking change is the removal of a specific base template type in C++ in LLVM 19 (the Xcode compiler) and introduces errors when building Expo apps.

You may encounter an error like this:

298 |   static_assert(is_standard_layout<value_type>::value, "Character type of basic_string_view must be standard-layout");
299 |   static_assert(is_trivial<value_type>::value, "Character type of basic_string_view must be trivial");
> 300 |   static_assert(is_same<_CharT, typename traits_type::char_type>::value,
     |                                          ^ implicit instantiation of undefined template 'std::char_traits<unsigned char>'
301 |                 "traits_type::char_type must be the same type as CharT");
302 | 
303 |   // [string.view.cons], construct/copy

Fixed Packages

The following packages have been patched:

expo-device@7.0.3
expo-gl@15.0.5
expo-dev-client@5.0.18
expo-dev-menu@6.0.23 (installed by expo-dev-client)
expo-dev-launcher@5.0.33 (installed by expo-dev-client)

To upgrade these packages, run:

npx expo install --fix

React Native Compatibility

React Native versions older than 0.77 have the same issues. This was fixed in react-native@0.77.0 with an upgrade to the native dependency, Folly. You will need to use React Native 0.77 or newer if you are using Xcode 16.3.

A fix for React Native 0.76 is in progress: facebook/react-native#50431.

For more information on using React Native 0.77 in SDK 52, see the React Native 0.77 release notes.