The Verge reports the new date for the launch as being May 21, though the company had originally planned an April 24 event.
Sources familiar with the plans are quoted by The Verge as saying the event will be held at a small venue and provide the first details on the new Xbox.
Staff have been instructed to remain tight-lipped on the new console, after Microsoft was forced to issue an apology last week after creative director Adam Orth publicly discussed rumours the new console required an always-on internet connection.