Apple's Worldwide Developers Conference (WWDC) starts this Monday, June 3, with a stage presentation by Apple executives at 10am Pacific Time. WWDC is usually one of the two biggest Apple events of the year (the other is the now-recurring iPhone/Apple Watch event in the fall), and it generally focuses on software.

It has become tradition for Apple to introduce new versions of its operating systems to developers at WWDC. Those systems include iOS for iPhone, iPad, and iPod; macOS for Mac; watchOS for Apple Watch; and tvOS for Apple TV and Apple TV 4K. In fact, these are some of the primary purposes of the event. So you can expect to see detailed presentations during Apple's keynote on each of those, plus deeper dives for developers in the various sessions at the convention center, which will also be made available as videos on Apple's developer portal.

To prepare for the event, we're recording what we deem to be the likeliest-to-be-true rumors, reports, and predictions ahead of the show—not just for software, but for hardware, too.

Let's dig in.

iOS 13

We'll start with iOS. Much of what we know about iOS 13 comes from a recent Bloomberg report , as well as a handful of leaks shared by 9to5Mac in recent weeks. Apple focused iOS 12 on fixing bugs and improving performance on older devices, with the company postponing some features to iOS 13. It's likely iPhone and iPad users will finally see some of the features they didn't get last year, but performance and stability remain a focus.

With those priorities in mind, Apple has, in fact, made some big changes to how it approaches developing iOS over the past year or two. We don't know much about exactly how performance will be improved, though. The Bloomberg report says there will be new, perhaps faster animations for the multitasking interface and for closing apps.

When it comes to new features, though, we know a little more.

Dark Mode

We've seen multiple reports citing reliable sources that Apple will bring Dark Mode—which was introduced to macOS with last year's 10.14 Mojave update—to iOS devices. Just this week, 9to5Mac published what it believes to be screenshots of Dark Mode (pictured above). It's a boon for users who find themselves using their phones in bed late at night or while watching a movie or TV in their home theater, for sure, but glare on those glossy screens will mean you'll probably want to keep the standard light mode on when out and about during the day.

iPad improvements

While we don't have many details, multiple reports have said that the iPad will get a new multitasking interface and that there will be long-asked-for changes to the home screen as well. Further, Apple plans to introduce a way for users to easily cycle between different versions of the same application, though it is unclear what the benefit of this would be to mainstream users. (Obviously, developers and some power users could benefit from this tremendously.)

A 9to5Mac report also citing sources familiar with Apple's plans said some kind of new windowed application interface will be introduced—this may be the same thing as the Bloomberg report's note on multitasking, or it could be something else. In any case, according to 9to5Mac, "Each window will also be able to contain sheets that are initially attached to a portion of the screen but can be detached with a drag gesture, becoming a card that can be moved around freely." Users will be able to stack the cards or dismiss them with some sort of gesture.

Finally, the sources behind the same 9to5Mac report said that Safari on the iPad will begin defaulting to the desktop version of websites instead of the mobile version whenever possible.

Updated apps

Tweaks to existing apps that are made by Apple and included with the OS are expected with each new iOS release. Apple is expected to make notable changes to Mail, Health, Messages, Maps, Books, and particularly Reminders.

For example, the Bloomberg report says that Apple will make it easier to access and track saved locations in Maps. The report also says that users will be able to mute threads in Mail, the Health app will display new and different information on its main screen, and Reminders will get a much-needed total overhaul.

Safari usually sees some big changes; this time, rumor has it that Apple will introduce a new downloads interface—at least on iPad. Apple may also combine the somewhat-infrequently used Find My Phone and Find My Friends apps into one.

Other iOS changes

The Bloomberg report also indicated that Apple will introduce a SwiftKey-like swipe keyboard. These have been available as third-party apps for quite some time, but like any platform holder with an abundance of resources, Apple has generally not hesitated to undercut developers with its own first-party version of a concept popularized by the developer community in the past.

Finally, Apple reportedly plans to introduce several new parent-focused features for Screen Time, the Settings panel that came out last year. Screen Time lets users control what apps and content can be accessed when, as well as track their usage with helpful metrics.