[keltex]

I've been playing around with Swift and SwiftUI for the past few months and the thing that baffles me is why are certain features only available with a minimum iOS version.

For example async required iOS 15.0. Why is this tied to the OS? Why can't they include newer runtimes be downloadable like Node / Java / .NET etc?

Other examples are from SwiftUI. For example the NavigationStack appears much more useful than the older NavigationView but that requires iOS 16. Which means that you can't support anything older than an iPhone X.

[e28eta]

Here’s a blog post where they describe the rationale behind switching from app-specific swift versions to bundling it with the OS.

https://www.swift.org/blog/abi-stability-and-apple/

[macintosh-hd]

I think it comes down to Apple trying to avoid as much fragmentation as possible. Fragmentation makes debugging, troubleshooting, and development a nightmare. It’s not an objective good but everything has its trade offs.

[saurik]

FWIW, as the application developer, it increases fragmentation, as more of the code in your app is determined by what version of the OS the user is running. If Apple were developing and debugging everyone's apps, that argument would make sense (but, of course, they are not). If you truly want to minimize costs for development and debugging by minimizing fragmentation you want to provide the most uniform and stable interface as possible for the developer and let the app then operate as identically as possible across every device it will ever work on, not just today but into the future.

[clawoo]

Joke's on them because debugging is already a nightmare.

I've been using Swift since its inception, it's been years since I've been able to pause execution at a certain breakpoint and do "po object" and get something back that is not an error.

[newZWhoDis]

Well for starters, if you were actually playing around with async/await on iOS you’d quickly find out it was back ported to iOS13.

It is frustrating though, although in my case 40% of my DAU are already on iOS 17 (>3m devices) so it’s not the end of the world.

[saled]

My understanding for the reasoning behind this is that they don't want apps to have to ship the runtime stuff to avoid downloads and app sizes getting large.

That could be fixed by just shipping an updated shared library to all phones similar to how Google play services works on Android, but I guess they figure if you're updating anyway you might as well just update the whole OS.

[wahnfrieden]

ASync has been backported to 13

[eviks]

Yeah, that's a bad design that leaves many functional old devices in the dust