Recently, Apple released Swift 4 with several new features and enhancements. Despite being compatible with Swift 3, Swift 4 comes with several new and improved APIs.
For instance, Swift 4 requires developers to use redesigned APIs for strings, dictionary, set, archival and serialization. Also, it enables developers to create multi-string literals using simple syntax. Swift 4 further introduces a new codable protocol that makes it easier for programmers to serialize and deserialize custom data types while writing complex code.
At the same time, Xcode 9 adds a number of new functionalities to the latest version of Swift. The new language features and improved APIs will persuade many developers to migrate their apps from Swift 3 to Swift 4. Apple keeps the Swift 3 to Swift 4 migration process simple and fast.
Also, it allows developers to migrate their apps to Swift 4 smoothly by taking advantage of the migration tool provided by Xcode 9. But the developers still need to keep in mind some important factors when they migrate to Swift 4.