Why framework build with low swift version can't import by the high swift version compiler

Using Swift
1

I build a swift framework with swift 5.7 compiler, then import it in another project. If I build the project with swift 5.9 compiler (compiler depend on the open source). There's such error:
/Users/yongluy/Downloads/applidium-OverlayContainer-7796f94/Example/OverlayContainer.framework/Modules/OverlayContainer.swiftmodule/arm64-apple-ios.private.swiftinterface:80:113: error: call to main actor-isolated initializer 'init()' in a synchronous nonisolated context

  • @_Concurrency.MainActor(unsafe) public init(dimmingView: OverlayContainer.OverlayContainerSheetDimmingView? = TransparentOverlayContainerSheetDimmingView(), presentedViewController: UIKit.UIViewController, presenting: UIKit.UIViewController?)*
  •                                                                                                            ^*

UIKit.UIView:38:24: note: calls to initializer 'init()' from outside of its actor context are implicitly asynchronous

  • public convenience init()*

failed to build module 'OverlayContainer'; this SDK is not supported by the compiler (the SDK is built with 'Apple Swift version 5.7 (swiftlang-5.7.0.127.4 clang-1400.0.29.50)', while this compiler is 'Apple Swift version 5.9 (swift-5.9-RELEASE)'). Please select a toolchain which matches the SDK.

But if build this project with Xcode15 default swift comipler. It is always build successfully. Thanks you to share your points! ;-)