South Africa have named Quinton de Kock as their new captain in ODIs, with his first series leading the team to come against England.
Faf du Plessis will not quit as captain before the fourth Test but it could be his last at home in the longest format.
England took 10 wickets for 103 runs on day four of the third Test and Mark Boucher delivered a few home truths to the Proteas.
South Africa lost a heart-breaking match against England late on day five, but Faf du Plessis knew he had been involved in a great occasion.
The T20 World Cup marks a "crossroad" in the career of Faf du Plessis, who will be 36 by the time of the tournament.
Opening batsman Pieter Malan will get his first taste of Test cricket against England at Newlands in the absence of Aiden Markram.
After South Africa followed up a tumultuous period with a first-Test win over England, Faf du Plessis said: "We needed that."
Captain Faf du Plessis believes Mark Boucher's experience of playing and coaching can make his a success in a new era for South Africa.
South Africa could be able to call upon AB de Villiers for the T20 World Cup in Australia next year.
After a series of off-field issues for Cricket South Africa, Faf du Plessis has said: "The attention needs to be on the cricket."