The legendary DJ, producer, remixer (etc) has been remixing with stems live on his Twitch stream for at least a year now. For many, he creates the stems using standalone software, then packages them into Traktor format.
More recently he's taken the stems from original master multitracks and played two packs in sync to get 8 tracks.
He's doing this live on Saturday 19th Nov at Public Records, Brooklyn NY from 11pm (it's being recorded).