Swift 3 is the first major release of Swift since Apple made it open source last year. Numerous improvements have been implemented in the first beta preview, and there are more to come in 2016. Getting familiar with these changes and the driving principles behind Swift's evolution will help you move forward confidently as even more changes are implemented before the final release.
Get your first look at Swift 3 in this course with Scott Gardner. Scott demonstrates changes made to the Swift Standard Library and Cocoa and Cocoa Touch APIs and reviews the Swift API Design Guidelines, identifying key principles and best practices that will help you optimize your Swift code. Also, check out the migration case studies in chapter 3, which show how to upgrade existing projects to Swift 3.