What is new in Swift?

Data Race Safety: Swift 6 introduces a new language mode that provides data race safety guarantees, helping developers write correct concurrent programs. This is a significant improvement in ensuring code safety and maintainability.
Non-Copyable Types: Swift 6 introduces non-copyable types, which are not copyable by default, enhancing memory management and performance.
Embedded Swift: A new language subset called Embedded Swift is introduced, which can run on highly constrained systems like operating system kernels and microcontrollers.

Concurrency Model: Continued refinements to the concurrency model, including async/await, actors, and structured concurrency.
Data Race Checking: Significant improvements to data race checking, ensuring safety and complete concurrency checking in Swift 5.10 and beyond.

Swift Testing: An all-new testing framework named Swift Testing has been introduced, built from the ground up for Swift. It features expressive APIs that simplify writing tests.
Swift Package Manager: Enhancements to the Swift Package Manager, making it easier to manage dependencies and build cross-platform applications.

C++ Interoperability: Improved interoperability with C++, making it easier to integrate Swift with existing C++ codebases.
Foundation Updates: Updates to the Foundation framework, optimizing it for Swift and enhancing its capabilities.

GitHub Migration: The Swift project is moving to a new organization on GitHub (swiftlang), which will include the Swift Compiler foundation and many more Swift ecosystem packages.

For more detailed information, you can watch the session What’s new in Swift starting at 17:03.