Ferrari and Honda have become the first power unit manufacturers to spend a portion of their allocated update tokens as they look to make up ground on their respective rivals.
A technical directive from Charlie Whiting confirmed that Ferrari had used three of its tokens, while Honda has spent two on its power unit.
The two manufacturers had started the year with 10 and 9 tokens to use across 2015 respectively, whereas Mercedes and Renault had 7 and 12 from a possible 32.
The token spend comes ahead of the Canadian Grand Prix – at the notoriously high-speed Circuit Gilles Villeneuve -, though it is unclear whether the upgrades will come in time for the race or the next event in Austria.
Though an engine freeze was imposed for the 2015 season, an amendment to the rules allowed a degree of development to take place using a token format. Honda was originally exempt from this, but was eventually allowed its own tokens to spend based on an average of those not spent by rivals.
Remaining Power Unit tokens to be spent in 2015
Mercedes – 7
Ferrari – 7
Honda – 7
Renault - 12