It looks like Apple could be shaking up its typefaces again. A report from 9to5Mac indicates that the forthcoming releases of iOS and OS X will use the Apple Watch's "San Francisco" as the system typeface, moving away from the Helvetica Neue typeface introduced in iOS 7 and OS X Yosemite.

The typeface, available for registered Apple developers to download here, is "designed specifically for legibility on small screens." We've included a comparison of the "ultralight" weight of both typefaces above.

Two things are immediately apparent—first, San Francisco is just a shade heavier than Helvetica Neue at the same size and weight. Second, San Francisco is narrower horizontally, which is doubtless helpful when you're working with a screen as small as the one on the Apple Watch. It's harder to say how the typeface would work with the wide variety of screen sizes (and the Retina and non-Retina displays) available across all iOS and OS X product lines, though 9to5Mac has some mockups and other screenshots that give you a rough idea.

You can expect more next-generation iOS and OS X details to come to light as we get closer to their respective unveilings at WWDC in June. The Apple rumor mill isn't always a reliable source, but it does tend to get more accurate the closer you are to an announcement or launch. So far the biggest news is that iOS 9 will focus primarily on speed and stability after the tumult of iOS 7 and 8, but beyond that, we're still waiting for the new operating systems to come into focus.