RocketLaunch (Next Rocket Launch) is a free SwiftUI teaching app with feature actors, three providers, deliberate failure handling and a GCD comparison project.

Swift concurrency vs Combine compared on network calls, timers and debounced search, with AsyncStream code, a decision table and a gradual migration path.

Enable complete concurrency checking in Xcode or Package.swift, switch targets to Swift 6 mode, and optionally use default MainActor isolation. Tested.

Strict concurrency checking is Swift's compile-time data-race checker. See Minimal, Targeted, Complete and Swift 6 mode compared on the same code.

No deadline for Swift 6 language mode, but since 28 April 2026 App Store uploads need Xcode 26 (Swift 6.2). Here's what's required and what's optional.

Big bang, file by file or feature slices? A behaviour-first, slice-by-slice Swift 6 migration strategy with leaf modules first and tested CFA examples.

Xcode 26's Swift 6.2 compiler still builds Swift 5 mode. Learn what Swift 6 mode changes, which upcoming features it enables, and how to switch per target.

Migrate to Swift 6 feature by feature: record behaviour, enable complete checking, wrap callbacks, move state to owners, then switch targets. Tested code.

Swift 6 turns Sendable violations into errors but allows safe hand-overs with region-based isolation and sending. See what changed, compiled in each mode.

Make a class Sendable with final and let, a Mutex, an actor or @MainActor, and use @unchecked Sendable only as a last resort. Tested with Swift 6.2.

A @Sendable closure may run in another concurrency domain, so it can only capture Sendable values. Learn the errors, fixes and sending vs @Sendable.

Swift 6 enforces @MainActor isolation, requires owners for static state, drops wrapper inference, and Swift 6.2 adds default MainActor and isolated deinit.

MainActor.run hops to the main actor and back. Learn when it fits, why @MainActor ViewModels don't need it, and how to migrate DispatchQueue.main.async.

Should you use @Observable or ObservableObject in SwiftUI? Per-property tracking, a runnable demo, a migration mapping and the traps to avoid.