Microsoft's next generation Xbox 720 'Durango' will be revealed at an event on May 21, according to numerous sources. The event, originally scheduled for April, was pushed back to May.

Microsoft expert Paul Thurrott announced that we should expect Microsoft's reveal of the new Xbox in May. He said, "Originally they were going to announce this thing in April, April 24, now they're going to announce it, you know, May 21^st," during the show What The Tech on Friday.

Thurrott also revealed on the show that the next-generation Xbox that is code-named 'Durango' will cost a lot: $500. A smaller version may be released for $300 with a subscription.

Thurrott also talked about a Microsoft release of an Xbox that wouldn't play games, but would compete with Apple TV or Roku. "That device was codenamed 'Yuma' and they're not making it. They may make one in the future but it's not happening this year."

However, a video media center box like Roku may be released in the form of a cheaper Xbox 360, codenamed 'Stingray,' and priced at $100. Thurrott said that he thinks Microsoft would do this to keep the Xbox 360 market alive, since it's unlikely that the $500 Xbox will play Xbox 360 games.

Finally, Thurrott said that the information he found out "a long time ago" about this upcoming Xbox included a reference to always being online.

"...it actually says, 'must be Internet-connected to use,' that's in the notes," he said.

Microsoft will reportedly officially unveil the new Xbox console at the E3 conference in Los Angeles in June. The product itself is expected to hit the market by November, in time for the holiday season.

A spokesperson from Microsoft declined to comment on the rumors, telling CNET, "We do not comment on rumors or speculation. We are always thinking about what is next for our platform, but we don't have anything further to share at this time."