For all those struggling with this, I found the fix. Make sure Swift Tools Version is 5.9 at the top of your package.swift file: // swift-tools-version: 5.9 // The swift-tools-version declares the minimum version of Swift required to build this package. Then you're allowed to specify iOS 17 in your platforms declaration: platforms: [.iOS(.v17)],

Hey @cyclic. Did you solve your issue? Unfortunately, when I try to use @Observable in a Swift Package I get the following error: "'ObservationRegistrar' is only available in iOS 17.0 or newer". You?