Apple will distribute a preview version of its next major operating system upgrade, code-named 'Panther', at an extended Worldwide Developers Conference, now rescheduled to June 2003.

The Worldwide Developers Conference (WWDC) was to take place in San Jose May 19-23. The event will now take place at San Francisco's Moscone Centre between June 23-27 - just days before the IDG-run Macworld Conference and Expo, New York, is scheduled to run.

Show organizers IDG World Expo and Apple have been involved in tense negotiations over the nature of the latter event since last year. This relates to IDG's decision to take the show to Boston in 2004, which Apple does not support. IDG World Expo has not officially released any information regarding the nature of the New York event this year.

Apple's vice president of worldwide developer relations Ron Okamoto said: "Our annual Worldwide Developers Conference provides our developers an in-depth look at the future of the Mac platform, and giving everyone a preview release of Panther is the best way to do that. Moving to June ensures that every developer will leave the event with a copy of Panther in their hands."

Apple has extended its 'Early Bird' discount pre-registration scheme to May 23. Developers who have already registered for the original event can contact their local Developer Connection representative to make new arrangements. Full information of what's available at WWDC is online.