What's new in Swift 6.2?

Swift 6.2 introduces several new features and improvements aimed at enhancing productivity and performance for Swift developers. Here are some of the key updates:

1. Strict Memory Safety: Swift 6.2 introduces a new mode called Strict Memory Safety, which requires explicit acknowledgment of unsafe API usage in the source code. This helps identify parts of the code that need extra security attention. This feature is being adopted in security-critical components like WebKit and a subsystem of the Messages app.

2. Concurrency Improvements: The language changes in Swift 6.2 make single-threaded code the default, reducing the risk of data races. It also makes it easier to introduce concurrency when needed, with improved support for async functions and mutable state.

3. Performance Enhancements: Swift 6.2 includes performance updates such as inline arrays, which allow arrays with a fixed size to be stored on the stack, and a new span type for safe, fast access to contiguous memory. These features improve performance, especially in embedded systems.

4. Development Workflow: There are improvements in the development workflow, including faster clean build times for projects using macro-based APIs and enhanced debugging for asynchronous code.

5. Library Updates: The core Swift libraries have been modernized, with new APIs introduced to streamline everyday programming tasks. This includes a new package for launching subprocesses.

6. Embedded Swift: Swift 6.2 expands the capabilities of Embedded Swift, making it suitable for highly constrained environments like firmware for embedded devices.

For more detailed information, you can watch the session What’s new in Swift (00:00:00) from WWDC 2025.