Oleksandr Usyk relinquished his heavyweight world championships "to decide for himself" the final chapter of his career.
The WBC has now ruled that Agit Kabayel will be its new heavyweight champion, with the IBF and WBA still to decide what next for their newly-vacated belts.
Kabayel was the holder of a WBC interim title, making him the mandatory challenger and next in line to fight Usyk for the full championship.
WBC president Mauricio Sulaiman said: "Just finished an incredibly sensitive Zoom video call with Agit Kabayel, George Warren, Spencer Brown and some WBC board members in have confirmed that Agit is the WBC heavyweight champion of the world as per the WBC board of governors voting.
"Congratulations champ!"
Usyk has been an undisputed world champion at cruiserweight and twice over at heavyweight and is still undefeated as a professional boxer.
To retain his WBC, WBA and IBF heavyweight titles, Usyk was facing a raft of mandatory challengers.
But he only wants to fight once more in his career and has vacated his belts so he can plot out his own course to retirement.
"Now he wants to decide for himself what the final chapter of his career will look like, rather than allowing circumstances or mandatory title defences to make that decision for him," Sergey Lapin, CEO of Usyk's promotional company Ready To Fight told Your Site.
"He made the conscious decision to vacate his championship belts in order to bring new life to the heavyweight division, give new champions the opportunity to prove themselves, and help move the sport forward."
An Olympic gold medallist, he has beaten the modern heavyweight elite, holding two wins apiece over Tyson Fury, Anthony Joshua and Daniel Dubois.
Last time out he picked up a late-stoppage victory over kickboxing star Rico Verhoeven in their crossover bout.
"I believe Oleksandr has achieved almost everything that can be achieved in boxing. He has already secured his place in history as the undisputed champion in two weight divisions," Lapin said.
"We prefer to take things step by step. Right now, our full focus is on the next challenge. When Oleksandr feels the time is right, he will make that decision himself.
"He has earned the right to decide when and how to close this chapter."
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