It sounds like you're trying to link against an older Swift runtime while targeting a newer OS.
It turns out that at the Project level, not the Target level, someone had defined:
LIBRARY_SEARCH_PATHS = (
"\"$(TOOLCHAIN_DIR)/usr/lib/swift/$(PLATFORM_NAME)\"",
"\"$(TOOLCHAIN_DIR)/usr/lib/swift-5.0/$(PLATFORM_NAME)\"",
"\"$(inherited)\"",
);
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After removing that, and making sure everything is targeting iOS 13.5, the error has gone away. Thanks for your help Joe ![]()