Users running this specific build (18D42) have documented several common software and hardware hurdles: Format on Save breaks Template Literal Variables #67989

While designed for stability, users on some older hardware (like 2012–2015 iMacs with 5400 RPM hard drives) reported slow performance or "beach balling" after upgrading.

This version is no longer receiving security updates and is considered an older legacy release. Key Features & Changes

This update primarily addressed security vulnerabilities, including a fix for a major FaceTime eavesdropping bug (Group FaceTime security flaw).

It is a popular target for "macOS Mojave Patcher" tools used to run Mojave on officially unsupported Macs. Reported Issues & Troubleshooting