User blog comment:Jimeee/Skyrim 1.9 beta update adds Legendary difficulty and raises level cap (Updated Apr 8th)/@comment-46.208.159.61-20130324081325/@comment-101.103.179.30-20130326155901

Hate to disappoint you but their twitter say they will send it for cert testing next week. Cert testing can take 1-2 weeks, also this is assuming that the cert testing gets the all clear to release. So I'd expect it to be out by mid-April at best.