Well, this is pretty unambiguous: mid-June …although, with the caveat “hopefully” …

I’m skeptical, considering the history.

http://www.iflscience.com/editors-blog/uk-government-to-release-secret-dossier-of-all-british-ufo-sightings-after-election-next-month/

Also, if you find this sort of thing interesting, please see my review of The Halt Perspective at https://emilvenere.com/fringe.html