: Use your Apple ID to log into the Apple Developer portal. You do not need a paid developer membership; a free account works. Search : Type "Xcode 10.1" into the search bar. Download : Locate Xcode 10.1 and download the .xip file. Extract : Double-click the .xip file to uncompress it.

Since the App Store will likely block you with a "macOS 10.15 or later required" error, you must download it manually from the Apple Developer site. Xcode want install on high Sierra 10.13.6 - Apple Developer

His client, a small railway museum in the Czech Republic, had paid him 800 euros to rebuild their archival kiosk software. The problem? The museum’s touch-screen kiosks ran an ancient embedded version of macOS. They couldn’t be updated. And the Xcode project, written by a long-departed contractor in 2017, required a specific, almost mythical version of Apple’s development tools.

: It includes Swift 4.2.1 and SDKs for iOS 12.1, macOS Mojave 10.14.1, watchOS 5.1, and tvOS 12.1. Limitation

If you need newer Xcode: