I'm confused on the official papers it's written that Pepe Kalle was born in 1951 and Wemba in 1949 (alot of people say that he was in reality born in 1947) . But Wemba was calling Pepe Kalle his "vieux" in interviews.

He was born in 1951, but was viewed as Vieux because of his commanding presence. Yampanya also used to resolve artist conflicts back in the day, so he had an elevated amount of respect.

I have noticed lots of websited getting his birth month wrong though. He was born in December. This article written during the period when he passed gets the facts right
http://next.liberation.fr/culture/1998/12/16/un-geant-de-la-rumba-disparait-le-zairois-pepe-kalle-est-mort-a-47-ans_253533