With three teams having left the 18-team four-conference competition is now a 15-team, three-conference format.
Gone are South African sides the Southern Kings and Cheetahs, who have joined the European Pro14 competition, and Australian team the Western Force.
Next year each team will play 16 conference matches, with eight matches within their own conference home and away, then four matches against teams from each of the other two conferences.
The change means South African team and this year's losing finalists the Lions, who didn't play any New Zealand team during the regular season in 2017, will play four New Zealand sides next season.
The 2018 competition starts on February 17th when the South African Conference kicks-off with the Stormers hosting the Jaguars in Cape Town. The Lions, runners-up the last two years, host the Sharks in Johannesburg, while Bulls have a bye.
The Australian and New Zealand Conferences will kick-off a week later in round two. Defending champions the Crusaders opening the defence of their title at home against the Chiefs and the Highlanders hosting the Blues. The Hurricanes begin their season with a clash against the Bulls in Pretoria.
The Brumbies, last year's Australian Conference winner, open the season against the Sunwolves in Tokyo who are now positioned in the Australian Conference.
The Lions and Crusaders will play a rematch of this year's final in Johannesburg on April 1.
There will be 120 regular-season matches, then eight teams will qualify for the finals. The final is on August 4.