我的理解是模块稳定性刚刚包含在 Swift 5.1 中.Swift 5 好像还不能使用用 Swift 5.1 编译的框架，因为还不支持模块稳定性.

What I understand is module stability just included in Swift 5.1. Seem like Swift 5 still cannot use the framework that compiled with Swift 5.1 since module stability is not supported yet.

对于您的情况，需要使用特定 Swfit 版本的编译框架.即如果您要用于 Swift 5 项目，请使用编译的 Swift 5 导出您的 SDK.Swift 5.1 项目也是如此.

For your case, need to use compiled framework for specific Swfit version. i.e. If you gonna use for Swift 5 project, export your SDK with Swift 5 compiled. Same goes to Swift 5.1 project.

Swift 5.1，实现模块稳定性https://swift.org/blog/swift-5-1-released/

Swift 5.1, Module stability implemented https://swift.org/blog/swift-5-1-released/

Swift 5.0，模块稳定性仍在开发中https://swift.org/blog/abi-stability-and-more/

Swift 5.0, Module stability still under development https://swift.org/blog/abi-stability-and-more/