iOS 13 is expected to be the star of WWDC 2019, but this year’s conference could unleash some of the biggest changes for the Mac we’ve ever seen.

The rumor mill has been dishing out tons of details about macOS 10.15 in the lead up to WWDC 2019. We’ve already seen screenshots of some of the new apps and gotten some good details on how iOS apps are making their way onto the Mac. There’s still plenty of room for Apple to surprise us when it reveals the full details of macOS 10.15 on June 3, but here’s what we know about it so far.

Evidence of Apple’s plan to break up iTunes has been uncovered ahead of the next major macOS update.

Icons for new Podcasts and TV apps have leaked out early. They’re expected to be accompanied by a new Music app and a redesigned Books app — all based on their counterparts for iOS.

Apple confirmed during its big WWDC keynote on Monday that iOS apps are coming to macOS.

The company has spent two years developing the frameworks required to make the ports possible. Several of its own iPhone and iPad apps, including Apple News and Voice Memos, will be available inside macOS Mojave this fall.

In a new interview, Craig Federighi, Apple’s senior vice president of software engineering, reveals more about how iOS apps will work on a Mac. He also promises that they won’t make your Mac feel like a super-sized iPhone.

Near the end of Monday’s WWDC 2018 keynote, Apple’s Senior Vice President of Software Engineering Craig Federighi addressed a question that’s been circulating in the tech press for a while: Are Mac and iOS merging?

His answer was direct and unequivocal: “No.”

Then he delivered a “sneak peek” of Apple’s long-rumored cross-platform project codenamed “Marzipan.” In line with the past six months of rumors, the idea of the framework is to allow UIKit-based iOS apps to run natively on Mac. While that probably sounds exciting to Mac owners, it could yield an unwelcome unintended consequence. It could trigger a “lost year” for Mac apps.