Xcode 10.2.1 GM was released on 17 Apr 2019 and requires macOS 10.14.3+.
It can be downloaded from https://download.developer.apple.com/Developer_Tools/Xcode_10.2.1/Xcode_10.2.1.xip.
Release notes are located at https://developer.apple.com/documentation/xcode_release_notes/xcode_10_2_1_release_notes/.
The SDKs it contains are:
- iOS 12.2 (Build 16E226)
- macOS 10.14.4 (Build 18E219)
- tvOS 12.2 (Build 16L225)
- watchOS 5.2 (Build 16T224)
The compilers it contains are:
- clang 10.0.1 (Build 1001.0.46.4)
- swift 5.0.1 (Build 1001.0.82.4)