Earlier this month, we have reported about a tweet from Paul Thurrott who said that Microsoft plans to unveil the next-gen console at an event planned for May 21. And it seems he got it right as Microsoft has just announced the official launch date of the Xbox "Durango" console.
The company has sent out invitations to certain media for the event, which will be held on May 21 at Microsoft's headquarters in Redmond. Don Mattrick will be in charge of the presentation, and there will also be the Xbox development team who will participate in the launch of the new console.
This means that the new Xbox will be unveiled three weeks before the start of E3 in LA, where we can expect presentation capabilities of the console.