When Apple releases macOS 10.13 High Sierra this fall, it will include big behind-the-scenes improvements and a few upfront changes in core Apple apps like Safari, Mail, and Photos. The upgrade will be free, and High Sierra will run on all Macs that can run 10.12 Sierra now.

The most important change under the hood is a new file system called APFS (Apple File system), which is designed for modern needs like fast backups of massive amounts of data and optimal behavior when storing files on solid-state drives. The file system is the smarts beneath the Mac’s Finder, helping your Mac to keep track of all its data. The Finder itself won’t change much, but certain tasks like duplicating lots of data will be much faster.

Other low-level technology changes will enable developers to bring faster video streaming and playback to the Mac. Plus, they’ll be able to create graphically demanding apps that have even more realistic images, which is important for the fields of virtual reality and gaming.

More obviously, you can look forward to Safari providing a more enjoyable Web browsing experience, with fewer ads, articles opening in the less-cluttered Reader view, and no more auto-playing audio. You can customize all these settings, as well as the text zoom percentage, on a per-site basis.

Searching in Mail will be significantly faster, with a Top Hits area that Apple says will learn from you over time and get smarter about suggesting ideal results. Mail will also feature a redesigned split screen option that puts the compose window next to your messages, and your Mail archive will consume less drive space than before, thanks to better compression.

Photos gets a lot of attention from Apple in High Sierra, with a refined interface that should make it easier to find tools, syncing of facial recognition training between your Apple devices, new editing tools for fine-tuning and saturation, and fun choices for enhancing Live Photos. Also, Photos will finally allow integration with third-party editing apps like Photoshop and Pixelmator, along with support for printing projects to non-Apple print services, so you’ll have more choices in that area.

Overall, High Sierra looks like it will be a solid refinement on Sierra, with some core improvements for pro users and a nice collection of enhancements to apps that the rest of us use every day.