Today, Apple announced on its website that the official release date of macOS High Sierra will be September 25th.
As detailed at WWDC in June, macOS High Sierra features the introduction of several significant new and updated under-the-hood technologies including APFS, macOS’s new file system, Metal 2, which harnesses the power of your Mac’s GPU, and HEVC video compression. High Sierra also adds new features and refinements to existing apps like Mail, Photos, Notes, Safari, Siri, and more.
Apple hasn't announced a Golden Master seed of macOS High Sierra yet, but it should be released to developers soon. The GM seed gives developers a chance to finalize their macOS apps and submit them to the Mac App Store for approval before High Sierra is released publicly.
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