The non-async signature for WKNavigationDelegate's decidePolicyForNavigationAction has changed between iOS 17 and 18. In 17 it is func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping (WKNavigationActionPolicy) -> Void) In 18 it adds the MainActor attribute to the decision handler func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: @escaping @MainActor (WKNavigationActionPolicy) -> Void) We deliver xcframeworks to our customers with objects that implement this function, and when those customers upgraded to Xcode 16.0 / iOS 18, those frameworks broke despite ABI stability (since that's unrelated to the WebKit SDK's public signatures). I presume this is because the WebKit dependency in the iOS 18 SDK does not match the signature used those older frameworks (and the IDE errors seem to support this). We will of course deliver new frameworks targeting the new SDK, but that takes regression testing and release planning. In the meantime, this has been exacerbated by the fact that macOS Sequoia does not support Xcode 15. Those of our customers whose machines updated to Sequoia cannot build their projects at all until we're able to deliver frameworks that are compatible. Was this an expected change? I didn't see any deprecation warnings in iOS 17, and unless we're supposed to bundle WebKit within the framework somehow, I'm not sure how we could have done this without forcing the Xcode versioning on our customers. Is there a way we package this differently or some other solution to make our existing frameworks compatible with iOS 18 without having to target that SDK?