Apple has released Swift 4.1 (https://swift.org/download/) for developers, an upgrade of its programming language. It contains updates to the core language, including more support for generics, new build options, as well as minor enhancements to Swift Package Manager and Foundation.
There was also significant progress made in stabilizing the ABI, according to Apple. Swift 4.1 is a minor language release. It is source compatible with Swift 4.0.