There was no release that supported the iOS 18 SDK O-: That's incorrect. Swift Playground 4.6 was the first version that silently included iOS 18 SDK. https://wholesome.computer/@mattpat/113921289516156105 And, according to the release notes, Swift Playgrounds 4.4 was the first version that included iOS 17 SDK. It was released just four days after iOS 18 came out. https://developer.apple.com/swift-playground/release-notes/ So, the correct history is: Support for the iOS 26 SDK arrived 6 months after iOS 26 shipped. Support for the iOS 18 SDK arrived 4 months after iOS 18 shipped. Support for the iOS 17 SDK arrived 4 days after iOS 17 shipped.