What’s Changing?
All apps submitted to App Store Connect must be built with the latest SDK versions:
- iOS / iPadOS → SDK 26 or later
- tvOS → SDK 26 or later
- visionOS → SDK 26 or later
- watchOS → SDK 26 or later
Required Upgrades
To meet these requirements, ensure your development environment is updated:
- macOS → Version 26.4 (Tahoe)
- Xcode → Version 26
Common Issue After Upgrade
After upgrading, you might encounter a build issue related to the fmt library (v11.0.2) when running the app on a physical device.
This happens because the newer Apple Clang compiler in Xcode 26 has compatibility issues with consteval.
Workaround Fix (Podfile Patch)
Add the following snippet inside your existing post_install do |installer| block in your Podfile:
# Workaround for Xcode 26: newer Apple Clang breaks consteval in fmt 11.0.2
# Patch base.h to disable consteval since the header doesn't check for pre-defined FMT_USE_CONSTEVAL.
fmt_base = File.join(installer.sandbox.root, 'fmt', 'include', 'fmt', 'base.h')
if File.exist?(fmt_base)
content = File.read(fmt_base)
unless content.include?('Xcode 26 workaround')
patched = content.gsub(
/^(#elif defined\(__cpp_consteval\)\n# define FMT_USE_CONSTEVAL) 1/,
"// Xcode 26 workaround: disable consteval\n\\1 0"
)
if patched != content
File.chmod(0644, fmt_base)
File.write(fmt_base, patched)
end
end
end
Final Steps
- Add the snippet to your
Podfile
- Run:
pod install
- Clean and rebuild your project
References
Tip: Don’t wait until the deadline. Upgrade early to identify and fix compatibility issues in your dependencies.
✍️ Written by Dainy Jose — React Native Mobile Application Developer with 3+ years of experience building cross-platform mobile apps using React Native (Expo, TypeScript, Redux).
Currently expanding backend knowledge through the MERN Stack (MongoDB, Express.js, React.js, Node.js) to create more efficient, full-stack mobile experiences.
💼 Tech Stack: React Native · TypeScript · Redux · Expo · Firebase · Node.js · Express.js · MongoDB · REST API · JWT · Jest · Google Maps · Razorpay · PayU · Agile · SDLC · Git · Bitbucket · Jira
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