Even by the standards of recent macOS releases, this year’s High Sierra is shaping up to be a low-key release with few high-profile user-visible improvements. Apple’s highlight page covers quite a few things, but in most cases they’re iterative tweaks that would mostly belong in the “grab bag” section of an overview of, say, Leopard or even Yosemite. Don’t get me wrong, I’m looking forward to iCloud-backed iMessages and family iCloud storage plans, but support for tables in Notes and flight status updates in Spotlight aren’t exactly life changing (not unless your life is continuously interrupted by extremely small and specific problems).

But to call High Sierra a minor release is to ignore the big under-the-covers changes it brings to the Mac, some of which have been in the works for years now. New filesystems and graphics APIs may be hard to demo to more casual users, but there’s plenty in this release that lays the foundation for more visible changes somewhere down the line.

In lieu of a traditional preview of High Sierra, we’ve browsed the dev docs and talked with Apple to get some more details of the update’s foundational changes.