Apple is a mobile device company. It makes the vast majority of its money from the iPhone, and everything else it does is starting to look a little like a side hustle. The real game for Apple is in these mobile devices, and the software that runs on them is the most important software that Apple makes. That software, of course, is iOS.  But iOS is much more than just the software that runs on the iPhone. It’s the closest thing we have to seeing what Apple envisions for the future of computing; heck, CEO Tim Cook said as much on stage when he introduced the forthcoming iPad Pro.

So Apple doesn’t take it lightly, and it very rarely makes drastic or sweeping changes to it. That careful approach is in full view with iOS 9, which will be available for download for free on most iPhones, iPads, and iPod touches starting today. There aren’t any major visual changes in iOS 9, especially on the iPhone, and it feels very similar to iOS 8 and even iOS 7.  That doesn’t mean Apple hasn’t been hard at work — iOS 9 is a much more stable experience than iOS 8 was when it launched, and there are a few new features here that are genuinely useful. But if you pay close attention, you can get a glimpse at the future Apple is planning for computers. And that future looks pretty great.

iOS 9 is not a shock and awe visual redesign like iOS 7 was two years ago. Install it, and you might be hard-pressed (no iPhone 6S pun intended) to tell the difference between it and iOS 8. The visual updates are subtle: there’s a new font called San Francisco, an updated keyboard with distinct uppercase and lowercase characters, and a revamped notification center that finally groups alerts by time and date, and not by app. iOS 9’s Notification Center still lacks a Clear All button, but the new grouping by date makes it much easier to clear batches of alerts than before.

Under the hood, Apple says it’s improved efficiency and performance across the board, and iOS 9 can squeeze out another extra hour away from the charger over iOS 8. In practical use, I haven’t noticed a huge difference in stamina or performance with iOS 9 on the iPhone 6. But the new Low Power mode, which lowers the screen brightness and disables some background syncing, does help out when you’re away from a charger. Apple says you can get up to three more hours of life than before, but I didn’t get results quite that good.

Over on the iPad, iOS 9 brings a few more significant updates, if you happen to have a recent iPad, at least. There’s a new split-screen multitasking mode, which lets you run two apps side by side. This drastically improves productivity on the device, as I can have a document open in Pages and reference a website or email at the same time. Another multitasking addition is called Slide Over, and it lets you temporarily slide one app partially over another to peek at it. It essentially shows you an iPhone view of that app, but your interaction is very limited: you can scroll around and input some text, but you can’t really do more than look before dismissing it and getting back to the task at hand. There’s also a new picture-in-picture video player that lets you have a video window hover over other apps, though it doesn’t yet work with a lot of apps where you might want to watch video (namely Netflix or YouTube).

Google has been pushing predictive intelligence for years, Microsoft has launched multiple generations of the Surface tablet / laptop hybrid, and Facebook is also working directly with publishers to accomplish many of the same goals as Apple News. And iOS 9 is still far from showing returns on any of these forward-looking bets. But while Apple is often far from the first to launch new ideas, interactions, or features, its implementations often prove to be better and longer lasting. I’m not saying iOS 9’s multitasking or prediction features are radically better than what we have on other platforms — frankly, they aren’t — but they lay the foundation for future improvements. It’s up to Apple to keep iterating on these features and improving them (which it does, once a year, with major iOS updates), turning this foundation into a skyscraper of future computing.

While iOS 9 doesn’t tower over any other platform yet, it is the ground floor of that skyscraper. I can’t wait to see where the elevator takes us next.