The Board of the FAI has approved the plan to restart the SSE Airtricity League season.
Earlier this week, the National League Executive Committee announced a plan to resume on July 31 with a truncated season.
After a contentious vote of 10 clubs to 9, the original plan for relegation and promotion will be retained.
The top flight season is reduced to 18-games apiece, including those that had already been played before the COVID-19 lockdown.
Sligo Rovers are among the sides unhappy with the format for the league's resumption.
Bit-o-Red treasurer David Rowe told Off The Ball earlier this week, "It's patently unfair and I know there's been court cases in other jurisdictions of similar decisions and talks of boycotts and all sorts of stuff.
"There's anger among nine Premier Division clubs."
— Off The Ball (@offtheball) July 1, 2020
Rowe added, "We signed up against our better financial judgement to compete because we're a soccer club and that's what we do.
"We were kind of inveigled into that on the belief that certainly the one up and one down and playoffs would not be the relegation proposal.
"We feel we've been mugged from all sides."
The 10-9 vote was won, largely thanks to a swing from Shamrock Rovers.
The Hoops were the only Premier Division side to vote in favour of the format that's now been greenlit by the FAI.
"We think if the promotion and relegation system was changed, it would have a dramatic effect on the First Division as well as the Premier Division," Rovers chairman Jonathan Roche told Off The Ball.
"We as a club expressed this opinion that it would drastically impact the competitiveness of the league if only one team is relegated and one team promoted.
"We have a different opinion to six clubs up until the other day when nine then expressed an opinion and that's where we are."