Linux版はswift-4.2.x-RELEASEを毎月出すらしい。 https://forums.swift.org/t/announcing-swift-4-2-2-and-monthly-swift-4-2-x-dot-releases-for-linux/20148

Announcing Swift 4.2.2 and monthly Swift 4.2.x dot releases for Linux

Announcing Swift 4.2.2 and monthly Swift 4.2.x dot releases for Linux We are very happy to announce the release of Swift 4.2.2 containing bug fixes for Linux. Much more excitingly, from now on we will be releasing monthly Swift 4.2.x dot versions for Linux over the next few m...