Three quarters of delegates backed a Central Council motion at Congress to introduce the change for the next three seasons.
Teams in Division Three and Four of the League will play in the new 16 team second tier, unless they reach their provincial final.
A Tipperary motion was carried to determine that Tier Two standings will be determined at the end of the League rather than at the start.
TD Calls For The Government To Get A Move On With South-Wicklow Greenway
Wicklow Councillors Demand €15m In Emergency Funding For Storm-Damaged Roads
Wicklow Hurlers Dominate Fermanagh To Ramp Up Promotion Hopes
Survey Shows Wicklow Families Want The Right To Deliver A Funeral Eulogy
Bray Vet Helps Reunite Wandering Pup with Owners