This was the final series of updates for Sierra before the transition to macOS High Sierra. Beta 5 (Build 16G23a) was released in late June 2017 to focus on security, stability, and small refinements rather than new features. Where to Find the DMG: While Apple maintains final versions (like the Sierra 10.12.6 Combo Update ), beta DMGs are often removed from the Apple Developer Portal after the public release.

A: The last supported Xcode for Sierra is Xcode 9.2 . You can download older Xcode versions from Apple’s developer downloads page after signing in. Alternatively, install only the Command Line Tools via xcode-select --install for a minimal development environment.

Running an older operating system like macOS Sierra 10.12.6 comes with inherent security risks.