i. What You Need

To follow along with this book, you’ll need the following:

• A Mac running Catalina (10.15) or later. Earlier versions might work, but they’re untested.
• Xcode 11.0 or later. Xcode is the main development tool for iOS. You’ll need Xcode 11.0 or later for the tasks in this book. You can download the latest version of Xcode from Apple’s developer site here: apple.co/2asi58y
• One or more devices (iPhone, iPad) running iOS 13 or later. Some of the examples in this book will run in the iOS 13 Simulator that comes with Xcode but most chapters require a physical iOS device for testing. The device must have an A9 processor or better.

If you haven’t installed the latest version of macOS or Xcode, be sure to do that before continuing with the book. The code covered in this book depends on Swift 5.1 and Xcode 11.0 — you may get lost if you try to work with an older version.