so, according to Billboard there will be no A-Listers, only alumni for Idol's final season up until finale...
According to sources, Idol’s final bow will feature only alumni of the show, saving the A-list bookings for the grand finale, scheduled for May 2016. "We will be bringing Idols back in a way that’s organic," says Trish Kinane, president of entertainment programming at FremantleMedia North America and Idol showrunner, stopping short of confirming the plan. "We’re going to be reflecting on the huge successes and amazing moments from the past 14 years." Says another insider: “It is too far out from the season” to speak definitively about guest spots.
accdg to the article, they will bring back alumni only which includes Kelly, Carrie, Adam, Phillip, JHud, Daughtry. BUT they won't have any A-Listers up until the finale
although she has no (new) music