Context

When building an Xcode project that uses the JSON-based .xcproj project configuration format (introduced in Xcode 27.0 or later), the following warning may appear in the build log:

JSON-based project.xcproj is not yet supported. Converting _.xcodeproj/project.xcproj to _.xcodeproj/project.pbxproj using `xcodebuild -convert-project`

Answer

No action is required. This warning is informational and does not affect your build or your repository.

This warning appears because your project uses the new JSON-based .xcproj format instead of the older .pbxproj format. This can happen if:

• The project was created with Xcode 27.2 or later, which uses the JSON-based format by default, or

• An older project was migrated to the new format.

Codemagic tooling does not yet support the .xcproj format directly. To read your project configuration and apply the correct code signing settings, it temporarily converts the project to the .pbxproj format during the build. This conversion happens only on the build machine and does not modify your repository in any way.