McLaren Honda
Honda, which this season will supply power units to McLaren, will be allowed to make limited upgrades to its power unit during 2015.
Honda has originally been informed that it must homologate its power unit before February 28, as the existing three manufacturers had to do so in 2014.
It was believed that Mercedes, Renault and Ferrari would have to abide by the same deadline in 2015 but a loophole was exploited, meaning that the 32 'tokens' - which allows manufacturers to upgrade 48% of the parts in the power unit - may be used across the duration of the campaign.
Honda expressed its unhappiness at the situation and held a meeting with the FIA in Paris last week, after which it was decided that Honda will be allowed to make updates, dependent on how many tokens rivals leave unused when the season begins in Australia.
"We will allow the new manufacturer to use the same number of tokens that the other three manufacturers have available to them, taken as an average of the three," race director Charlie Whiting said in a document, allowing scope for potential future entrants.
"For example, if the three 2014 manufacturers have eight, seven and five unused tokens respectively at the start of the season, then the new manufacturer will be allowed to use six during the season (the average rounded down to the nearest whole number)."
McLaren will unveil its MP4/30 on January 29.
