Apple kicked off its annual Worldwide Developers Conference (WWDC) with a slew of announcements about OS X, iOS, and the latest developer tools.

Apple

OS X Yosemite

The latest update to OS X is packed with subtle UI changes and improved utilities, some of them building on functionality from existing apps. Here are four of the key updates:

Spotlight: Spotlight now plants itself front and center on the screen. Taking cues from apps like Alfred, Spotlight will now display local and Web results in a single interface, even before you finish typing your search term. Apple has also integrated Maps, iTunes, and Mail into Spotlight, so Spotlight can pull up context-related results and mini widgets that allow access directly from the new search box.

Notifications and widgets: The notification panel now expands to show day-level activities, as well as swappable widgets from both Apple and third-party companies like ESPN.

Continuity: Apple has blurred the lines between Message, Phone, and FaceTime by allowing users to make and receive calls directly from OS X Yosemite. Apple promises seamless functionality -- dubbed Continuity -- between iPhone and computer through a combination of hotspots, Bluetooth, and device awareness. AirDrop also makes its debut on iOS devices with the same level of functionality it has on OS X.

Design: OS X Yosemite brings subtle design flavor from iOS, including redesigned icons, typographic improvements, and the frosted glass pane windows that now adorn the application and notification windows. Apple has also introduced a dark mode that lets you invert the header menus to a darker transparent theme.

Developers gain access to the current build of OS X Yosemite today, and the public can test-drive the beta this summer. Also check out the top updates for iOS 8.