The move will come as a great boost to managers everywhere, as they will no longer have to deal with depleted squads in January and February.
Players from 12 Premier League clubs took part in this season's tournament, but the new move will put it in line with other major tournaments and end the need for teams to release players mid-season.
The next installment of the biennial tournament will take place in Cameroon in 2019 and will include 24 teams, rather than 16.
From then on the tournament will continue to take place every two years, though plans to host the event in China and Qatar have been scrapped, with the organisers deciding to keep the tournament a truly African affair.
The changes were ratified by the CAF committee in Morrocco's capital, Rabat, on Thursday.