Download the macOS High Sierra 10.13.1 installer from the Mac App Store or Apple's support website.
Finding a can be tricky because Apple typically only provides the most recent version of an operating system (10.13.6) on their official servers. Official Download Methods macos high sierra 10.13.1 dmg
The 10.13.1 release wasn't just about features; it was a necessary security response. Download the macOS High Sierra 10