I noticed that running my app in Xcode 16 crashes often. It seems this is due to the strictness Swift 6 adds at runtime. Even after making sure the Swift Language Mode is 5 for the main target and all modules.
I'm migrating to Swift 6 but I probably won't be done before iOS 18 drops so my question is. Can I still ship the app supporting iOS 18 using Xcode 15.4 and Swift 5.10?
Also, I can't run Xcode 15.4 in macOS Sequoia, does it mean if I want to keep supporting 15.4 and Swift 5.10 without Swift 6 runtime checks I have to stay in Sonoma?
If your app doesn't use anything that's new in iOS 18 then you can continue to deploy it with Xcode 15.4 on macOS Sonoma.
You can't run Xcode 15.4 in Sequoia, and if Swift 6 is causing you issues, you may have to stay on Sonoma until you're ready.