Lewis Hamilton and Valtteri Bottas will both be equipped with a new specification of Mercedes engine for this weekend's French Grand Prix.
The team had originally planned to introduce the upgrade in time for Canada. However at the last minute a quality issue forced them to switch back to the old power units that the drivers had already used for six full races.
The FIA confirmed earlier on Friday that Mercedes had fitted new internal combustion engines, turbochargers and MGU-Hs to both their cars for this weekend.
However, the team had been tight lipped about whether these parts were the new specification.
It was only confirmed after the end of Friday practice - which saw Hamilton in dominant form in both sessions - that Mercedes had been confident enough to roll up the upgrade.
"Those new components are of an upgraded specification which contains reliability and performance updates,” the team said in statement.
“This is a Phase 2.1 with some ‘added goodness’ thanks to a fantastic effort by the team in Brixworth."
Mercedes has also supplied the upgrades to its customer teams, Force India and Williams. All six race units plus spares have been reworked.
The team wanted to make sure there were no unexpected issues on Friday before confirming that the power units would be used for the rest of the weekend at Circuit Paul Ricard at Le Castellet.
Hamilton ended the session seven tenths of a second ahead of Red Bull's Daniel Ricciardo. He was also fastest before lunch.
But Bottas' day ended early when his W09 suffered a water leak that affected cooling at the back of the car. Repairs meant removing the flooring of the car, and the time it took meant that he ran only seven laps in the afternoon.
However the issue did not appear connected to the new power units.
Confirmation that the upgrades will be available this weekend will be a big boost for Hamilton. He suffered in Montreal partly because of having to use the ageing units that were down on power compared to his rivals, who all had new engine parts for the Canadian Grand Prix.
Hamilton finished the race in fifth place, while Sebastian Vettel won. It meant that the ferrari driver took the lead of the drivers championship by a single point.