FIFA president Gianni Infantino said the change to more substitutes as part of the Laws of the Game, which was first allowed in 2020 because of the coronavirus pandemic, followed "strong support from the entire football community".
He said after IFAB's annual meeting that experts would decide on whether offside detection technology would be used for the World Cup that starts Nov. 21. FIFA's Referees Committee chairman Pierluigi Collina said he was "confident" the system would be introduced in time for the 32-nation tournament. Tests were carried out at the FIFA Arab Cup last year and Club World Cup this year.
The system monitors data points on the limbs of players to create a model that is reviewed pitchside by the referee.
"We are very satisfied so far and our experts are looking into it before deciding whether it will be introduced for the World Cup," Infantino told a press conference.
It is officially known as "semi-automated" as it will be the referee that makes a final decision on an offside.
FIFA is also looking into introducing a VAR system with fewer cameras to a wider number of competitions. It is currently only used at international tournaments and in some domestic competitions.
Tests on the less-tech heavy, cheaper system -- Var Light -- have already been held at 100 matches in Europe and will now be extended.
As well as making the five substitutions permanent, IFAB said that teams can now name 15 substitutes on a team sheet instead of 12, at the discretion of tournament organizers.
IFAB said that trials of referees wearing body cameras may be started in a bid to counter a growing number of attacks on match officials.
"The members agreed to establish initiatives to tackle these issues, including potential trials with body cameras worn by referees in adult grassroots football." The English FA has pressed for action to protect referees.
IFAB -- made up of the game's founding national associations from England, Scotland, Wales and Northern Ireland with FIFA -- could also start trials for kick-ins as an alternative to throw-ins.
"Proposals were made to test kick-ins," said Infantino. "Whilst we may be a bit sceptical on some of these measures... If some proposals are there to help the game, we will not know it before we look into it, so we will look into these proposals as well."
The rules body ordered trials on the use of concussion substitutes -- which has been tested in 140 domestic leagues and tournaments -- to be extended until August 2023.
Growing concern has been raised about the impact of head injuries on players -- with many suffering from dementia and Parkinson's disease in later life.
"The members agreed that trials should continue to focus on permanently removing any player with actual or possible concussion to ensure this player does not continue taking part in the match," said the statement.