Recorded by Nichoach (Vol 2.)There are multiple versions of this niggun. I heard that the Rebbe specified which "nusach" was correct for the Nichoach recording.
R' Michel Zlotchever composed this nigun when he was ill and could not visit the Baal Shem Tov..
According to the Rebbeim, the Besht asked this nigun to be sung before he passed away and then said whoever sings with true "Teshuva" the Besht joins in and is "mi'oirer rachamim" for the "baal teshuva" who is singing..
(Sefer HaNiggunim)