An invitation has been sent a couple of days ago and it is expected to see the release of OS X Yosemite and a new iPad (6th generation) likely to be called "iPad Air 2". There has also been rumours about some other Apple devices that are less likely to be announced but the might well be, for instance: iPad Mini 3, a 12.9 inches iPad, a retina iMac, a new MacBook Pro or Macbook Air.
Yesterday, Thursday, 28th August 2013, Apple sent out invitations for an event being held at 10.00 am, this time, not at the Yerba Buena Center in San Francisco but at the Flint Center for the Performing Arts in Cupertino.
Apple have announced some of the new features available in Mac OS X Yosemite and iOS 8 this Autumn. Some of the new features available in Mac OS X Yosemite and iOS 8 will be translucent backgrounds, a search bar that connects to Wikipedia and provide more information that the current and interoperability (called by Apple "continuity").