Apple sends out official invitation for Sept. 9 event

Apple invited reporters to a "special event" in its hometown of Cupertino, Calif., on Sept. 9, when the iPhone maker is expected to unveil the latest versions of its best-selling smart phones.

The launch date came as no surprise, as it had been widely reported. Apple is expected to unveil larger 4.7-inch and 5.5-inch screens for iPhones, a move thought to be driven in part by the success of archrival Samsung with its larger devices. The current iPhone 5S and 5C are both 4-inch devices.

Tech blog Re/code also reported that Apple may introduce its long-awaited smart watch. Such a device, often dubbed the "iWatch," could come in the form of a bracelet, similar to the now defunct Nike+ FuelBand, or in a more traditional watch design, such as the Pebble Steel. A bracelet shape would allow Apple to pack in extra battery space by distributing it throughout the band, while a timepiece design would likely give the iWatch room for a larger screen.

This fall will also bring the release of iOS 8, the next major software update for Apple mobile devices. Two big additions include HomeKit and HealthKit, apps that gather data from lots of different places. HomeKit will act as a central command center for the so-called Internet of Things, while HealthKit creates a single feed of exercise and fitness data.

Thursday's typically cryptic invitation read "Wish we could say more" on a simple black-and-white background dominated by Apple's familiar corporate logo. Apple often hides messages in its vague invitations. In 2012, before Apple debuted its new Maps app, the invitation said "It's almost here." When the company unveiled the colorful iPhone 5C line last year, invitations said, "This should brighten everyone's day."

"Wish we could say more" may hint at improved voice controls, but now we're in total speculation zone. 

All will be revealed Tuesday, Sept. 9.