ABI Stability and More

With the release of Swift 5.0, Swift is now ABI stable and is delivered as a core component of macOS, iOS, tvOS, and watchOS. ABI stability has been a goal for Swift since its inception, and brings with it many benefits for developers and users of these platforms.

→ swift.org/blog/abi-stability-and-more/

Swift 5 achieves ABI stability on Apple platforms, ensuring binary compatibility for apps and libraries across future Swift versions without needing to embed the Swift runtime in app bundles.

This means apps built with Swift 5 can run on systems with Swift 5 or later standard libraries, reducing download sizes as the runtime ships with the OS. Module stability, under development, will allow frameworks compiled with different Swift versions to be imported without compiler mismatches, while library evolution support enables API updates without recompiling client apps.