macOS High Sierra will ship on September 25th, according to information added to the High Sierra website. The date went unmentioned during Apple’s media event, and falls one week after iOS 11 ships.
High Sierra includes Apple File System, support for the HEVC 4K video codex (a.k.a. H.265), Metal 2 for graphics processing, the ability to create virtual reality content, improvements to Photos and other Apple apps, Intelligent Tracking Prevention in Safari, the ability to control autoplay videos, improvements to Siri and Spotlight, and a whole lot more.