High Sierra may require a firmware update for your Mac to support the new APFS file system; follow the on-screen prompts during the installation process.
If the official links do not work for your specific hardware, some users turn to third-party archives, though these should be used with caution: macos high sierra 10131 dmg
This update brought several "under-the-hood" improvements designed to modernize the Mac experience: High Sierra may require a firmware update for
Guide to macOS High Sierra 10.13.1 DMG The macOS High Sierra 10.13.1 update, released on October 31, 2017, was a significant technical refinement for the Mac operating system. While Apple primarily distributes macOS through the App Store, many users seek a file to create bootable installers, restore older hardware, or set up virtual machines . Official Download Methods some users turn to third-party archives