It means that the South African teams will be able to qualify for European games.
Tournament organisers have confirmed that the new 16-team PRO rugby competition will be called the United Rugby Championship.
South African clubs the Sharks, Stormers, Lions and Bulls will enter the league next season alongside the teams who competed in last year's Guinness PRO14.
It will see the return of a single-standing table with quarter-finals, semi-finals and a grand final at the end of the regular campaign.
Under the agreement, the South African sides will be eligible to qualify for European competitions.
Here's an explainer of how it will all work:
Everything you need to know ⬇️
— PRO14 RUGBY (@PRO14Official) June 15, 2021
One league table to rule them all... and regional tables to hype the rivalries!#URC pic.twitter.com/xkqeCBOEbf
Full Interview: Portarlington Footballer Ronan Coffey
Full Interview: The Down's Manager Dermot Power
St Brigid's And St Joseph's Aiming To Reach Leinster Semi-Finals
Ballinagar And Milltown To Meet In Leinster Intermediate Quarter-Final
Ronan Coffey Praises Portarlington’s Young Guns Ahead Of Leinster Quarter-Final
Mauricio Pochettino Set To Be Appointed Manchester United Manager
Darragh Murray Named In Irish Squad For Fiji Clash
Portlaoise Panthers Aiming To Bounce Back In Division One
Portarlington On The Road In Leinster
The Down's Building Towards Leinster Football Quarter-Final
Laois Provisional League Fixtures Revealed
The Harps Manager Praises His Sides Efforts In Leinster
Buccaneers Claim Back To Back AIL Wins
Kilcormac Killoughey Captain Full Of Praise For Goalkeeper
Lough Lene Gaels Suffer Late Heartbreak In Leinster Quarter-Final
Crookedwood Win Leinster Junior Camogie Title
Conor Slevin Wins Dramatic Leinster Quarter-Final For Kilcormac Killoughey
Ireland Secure Comfortable Win Over Argentina
Kilcormac Killoughey Seal Win But Heartbreak For Lough Lene Gaels And The Harps