Honda has used its remaining four engine development tokens for this weekend's Russian Grand Prix with an upgrade package that only Fernando Alonso will use.
Having spread its development token use over the season, with improvements having been delivered at the Canadian and Belgian Grands Prix, the Japanese car manufacturer has elected to introduce its final step for Sochi.
The tokens have been spent on improvements to the exhaust and the combustion of the engine.
Honda's push to get the upgrades ready for this weekend have meant that there were only enough items ready for one car, so it was decided that Alonso would be given them for this weekend.
The Spaniard will have to run a new internal combustion engine (his 10th of the season), a new turbo, new MGU-H, new Energy Storage and new Control Electronics.
The plan is for Alonso to run the upgrades as a test in first free practice, before reverting to the engine he used at the Japanese Grand Prix. Honda is also planning to introduce a new turbo and new MGU-H however.
The new components for the upgraded engine and his race unit will mean grid penalties, which will most likely mean he will start from the back of the grid.
Jenson Button is likely to take the upgraded engine at one of the next events, with it hoped that the power units will last until the end of the season.