There is a new document going around, that allegedly is a newly leaked MJ-12 document.

Unfortunately, this document is a fake, that is filled with errors and falsehoods. The US,e.g. doesn't use an 'Ultra' or 'Ultra Top Secret' classification. (The UK did decades ago, and some Latin American countries still have an 'Ultra Secreto'; but the US don't). The branch of the DIA that deals with counterintelligence is not called the 'Office of counterintelligence.' The document is filled with factual errors that a real report wouldn't have: Kirtland AFB, e.g., is in Albuquerque NM, not in Texas. Flat Rock, Nevada only exists in science fiction novels, etc.
Here are the conclusions of some researchers:
Kevin Randle: "I see that there really is nothing new here. The information about Roswell is wrong, the name of the base is wrong, the chain of command is wrong, and even the higher headquarters at Fort Worth is wrong (it wasn’t the 5th Air Force, but the 8th). The Aztec material is derivative of Steinman’s book, the MJ-12 information is taken from there (or maybe from any of Stan Friedman’s many writings on it), and there is nothing that is suggestive of advanced scholarship. The writing does not sound as if it came from a government source, and without names, without government agencies, without any way to check things out, this just doesn’t seem to be authentic. (... ) it it is now clear that this does nothing to further our knowledge and just confuses an already confused issue."
Nick Pope, who investigated the UFO phenomena for the UK Ministry of Defence (MoD) until 2009, described them as "fake with a capital F" (...) "These documents are completely and utterly bogus. The language and the wider feel of these UFO documents is just plain wrong. It's as if someone was playing buzzword bingo with all the words and phrases that excite UFO believers, and throwing in some New Age philosophy for good measure."
UFO publisher Philip Mantle claimed it was irrefutable they were fake, as they referred to a fictitious location in Nevada. He posted on Facebook: "The final nail in the coffin is. . . according to these documents, the SECRET MJ-12 HQ is under Flat Rock, Nevada, a fictional town invented for Michael Crichton's "Andromeda Strain" novel!"
Isaac Koi (a pseudonym) called this new "MJ12" document "A (poor) joke, rather than a hoax intended to actually fool anyone? Some of the names in this silly document appear to be taken from famous science fiction novels. "Digger Command" is a fictional entity in Vernor Vinge's novels. The location of "Flat Rock, Nevada" mentioned in the document is the _fictional_ setting of the lab in Michael Crichton's novel "The Andromeda Strain". (That fictional location has subsequently been borrowed for at least a couple of other science fiction novels). (...) I can't be bothered checking the entirety of the document for more."
[Quotes from Nick Pope and Philip Mantle are from www.express.co.uk/news/weird/818311/Roswell-UFO-aliens-proof-DIA-leak-fact-or-fiction].