: At least 2GB of RAM (8GB recommended) and 14.3GB of available storage . How to Download the macOS High Sierra Installer

This update brought several "under-the-hood" improvements designed to modernize the Mac experience:

: Improved the reliability of Microsoft Exchange message syncing in Mail and fixed bugs where Spotlight wouldn't accept keyboard input.

While modern Macs use newer systems, High Sierra remains a vital "bridge" OS for older hardware and specialized software environments.

: Fixed the widespread WPA2 Wi-Fi flaw (KRACK) that could allow attackers to decrypt network traffic.

Apple typically provides the installer through the App Store, though it is often hidden from search results on newer versions of macOS.

: Added 70 new characters, including animals like the T-Rex and hedgehog, mythical creatures like vampires, and more expressive smiley faces.

macOS High Sierra - Technical Specifications - Apple Support

: Enhanced SMB printing and added support for unlocking FileVault-encrypted APFS volumes using a recovery keychain. System Requirements High Sierra supports a broad range of legacy Mac hardware: MacBook : Late 2009 or newer MacBook Pro : Mid 2010 or newer MacBook Air : Late 2010 or newer iMac : Late 2009 or newer Mac Mini : Mid 2010 or newer Mac Pro : Mid 2010 or newer