Well, they've been locked away in the vault since 2014 at least.
@Clay7 You have the facts about the song right?
Unfortunately thats one i dont really know anything about outside of whats public. Weird how mysterious this song is for being likely the only actually finished song left that hasnt leaked we know so little about it outside of who worked on the Xscape version. MJ vocal was laid down in 1998 - 2003 although the exact year is unconfirmed.
Song was first known to exist in July 2010. According to John Branca and Michael Prince he did not record very many vocals which is why they brought in D'angelo and Mary J Blige for new vocals on the 2013 remix.
2013 Remix Creds:
Michael Jackson & D’Angelo (Feat. Mary J Blige)
"Hot Fun In The Summertime"
Production: Michael "D'Angelo" Archer
Vocals: Michael Jackson, Michael "D'Angelo" Archer, Mary J Blige
Lyrics: Sly Stone
Keys + Sitar: Ahmir "Questlove" Thompson
Guitar: Jesse Johnson
Drums: Ahmir “Questlove” Thompson
Bass: Pino Palladino
Horns: Eric “Ric” Leeds
Engineering: Russ Elevado, Ben Kane
Executive Producer: John McClain
This is the type of drum that was used by Queslove for the track to give some idea of how it may sound:
This is the type of guitar that was used by Jesse Johnson for the track to give some idea of how it may sound:
very interesting track im dying to hear it out of sheer curiosity with the credits, not a fan of the og track at all.