Apple Developer Weekly #224 Swift 6.1 and Xcode 16.3 Officially Released

iOS 18.4 Issues Are Severe

From 13

Generally speaking, Xcode and iOS versions released in March and April tend to be more stable, but this year really surprised me.

iOS 18.4 has several bugs: UITextView crashes, URLSession.shared fails in Simulator, and MusicKit issues. Square app even warned users not to update the system.

Have your projects been affected?

Additionally, Xcode 16.3 changed its behavior, causing InjectionIII Hot Reload to fail by default, requiring manual configuration of the EMIT_FRONTEND_COMMAND_LINES build setting.

What a busy week!

I'll be attending try! Swift Tokyo this week. Feel free to say hi if you're going too!

One more important thing: If you're going to Apple's headquarters for this year's WWDC, please email me. I already know 3 Taiwanese friends who are going, and I can help connect you and form a group.

13 on April 7, 2025

🛠️Swift 6.1 Released

Here are some highlights:

• Concurrency: nonisolated can now be applied to types and extensions.

• Improved type inference for TaskGroup child tasks (previously covered)

• Implementing Objective-C types in Swift is an eye-catching new feature. Just write @objc @implementation to implement Objective-C type content in Swift - it's super fun!

• Swift 6.1's SPM has a powerful new feature: Package Traits. Package authors can use this mechanism to provide features similar to compile configuration or feature flags for users to choose from. I believe this is a significant breakthrough for the Swift Package ecosystem. Don't miss it if you're using SPM.

• Swift Testing also has great new features called Testing Scoping Traits. There are many ways to use this - check out the original proposal or Point-Free's examples.

• Another quality-of-life improvement: when separating multiple parameters with commas, you can now keep the comma after the last element, just like with Arrays. The biggest benefit is reducing the hassle of modifying commas when swapping parameter positions.

• DocC's linking rules have become more user-friendly. For ambiguous methods with parameters supporting different types, links no longer need to be random. I've also noticed that in Apple's official documentation, some pages can expand methods with similar names.

• The installation tool swiftly mentioned in the previous issue

🛠️Xcode 16.3 Officially Released

This version of Xcode has been in beta for a long time and is finally officially released. The Release Notes show many fixes.

There are numerous updates and fixes for Preview, enhanced C++ interoperability and support for new versions, Instruments' Processor Trace Instrument feature, and xcodebuild's new -prepareDeviceSupport. These are just the tip of the iceberg - I recommend reading them yourself.

If it's too long, you can ask AI for help. Here's Gemini 2.5 Pro's summary.

🖥️ macOS 15.4 Update Highlights

• Support for setting up Mac accounts with iPhone: Previously only iOS and tvOS could be set up with iOS devices

• Added support for F16C/BMI instructions, improving GPTK game compatibility: Games like Horizon Forbidden West, Alan Wake 2, The Last of Us Part II, Spider-Man 2, and Ghost of Tsushima, which previously required patching exe files, can now run directly

• iWork apps updated to 14.4

🤡April Fools' Jokes

Compared to the iOS 18.4 situation, these April Fools' jokes aren't funny at all.

• UIKit is being deprecated

• Apple starts accepting GitHub sponsorships for Swift by Paul Hudson

• App Store Connect Report New Features

📖Understanding Audio Files: New WAV Format Chapter──zonble

Those who know zonble can appreciate the weight of this book. For those who don't, you should get to know him.

A must-read for developers working with audio.

🙋Community Updates and Recommendations

• If you're going to Apple's headquarters for this year's WWDC, please email me. I already know 3 Taiwanese friends who are going, and I can help connect you and form a group

• Swift by Sundell is back: John Sundell, who was very active in the Swift community, disappeared for two years after becoming a father. Now he's archived his old articles and started a new series. Welcome back!

• Global WWDC Community CommunityKit: Perfect for those attending WWDC in person, here's the Discord link

• Nintendo Switch 2 Developer Interview: The newly announced Switch 2, while seemingly unrelated to iOS developers, should provide much inspiration as Nintendo's products, like Apple's, are vertically integrated

📣Job Board

• @riddle_ling's freelance post, feel free to check it out

If you have iOS development-related job openings or resumes you'd like to post in the Developer Weekly, please see About.

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