Tech buffs are eager to know what is going to happen at the Moscone Center in San Francisco, now that a major event has been announced.

Apple has made it official that the 2013 Worldwide Developers Conference (WWDC) will take place from June 10 to 14. The tickets for the conference will go on sale April 25 with a price tag of $1,599. The Cupertino-based tech giant also makes it clear that the event is not an open-to-all program.

"To buy a ticket, you must be a member of the iOS Developer Program, iOS Developer Enterprise Program, or the Mac Developer Program as of the announcement of WWDC (5:30 a.m. PDT, April 24, 2013) and at the time of your ticket purchase. Developers between 13 and 17 years of age must have their ticket purchased by their parent or guardian who is an eligible member," Apple states on the official page of WWDC.

With the date, the venue of the event and the ticket restrictions now known, attention turns to the topic of "what has Apple got to unveil during the five-day program?"

We can guess there will be some announcement related to the advanced versions of Apple's mobile operating system, iOS, and the Mac operating system, OS X.

"Get an in-depth look at what's next in iOS and OS X, and learn how to take your apps to the next level. With over 100 sessions, extensive hands-on labs, and engaging events, you'll connect with Apple engineers and fellow developers for an incredible week of inspiration," the WWDC announcement page states.

Many rumors related to the upcoming mobile operating system from Apple, iOS 7, are circulating on the Internet and many designers have also shown their interest in the OS with their concept designs.

The chances of seeing a new iPhone or a mention of it seem to be very low, as we don't see Apple talking about any of its new devices right now.

Some reports, emerging earlier this month, suggested that the development of iOS 7 was running behind schedule and Apple had to ask the developers working on Mac OS X to chip in and help the developers of iOS 7 to finish the task faster.

Prominent blogger John Gruber dropped a clear hint at the Branch discussion and said, "What I've heard: iOS 7 is running behind, and engineers have been pulled from OS X 10.9 to work on it."