: Implemented High Efficiency Video Coding for better video compression. Apple Support Community Where to Find the Official Installer

Here is how to get the and then convert it to ISO yourself.

✅ You now have a of macOS High Sierra 10.13.6.

macOS High Sierra 10.13.6 full installer - Apple Support Community

(That sets the date to Jan 1, 2018). Run the installer, then reboot and set the date correctly.

An .iso file is a raw sector-by-sector copy of a bootable disc. Unlike a .dmg , many hypervisors (VirtualBox on Windows/Linux, Proxmox, ESXi) and firmware (BIOS/Legacy boot) treat .iso as first-class citizens. This makes 10.13.6.iso the gold standard for cross-platform virtualization.

Introduced "Intelligent Tracking Prevention," which blocked third-party advertisers from tracking user behavior across different websites—a major early privacy feature.