Mercedes has confirmed that it has spent five engine development tokens on upgrades to its power unit for this weekend's Belgian Grand Prix.
The news comes on a weekend when the German car manufacturer has elected to hand Lewis Hamilton new components because he was running short.
He is currently facing a 30-place grid penalty for the race because he had new parts fitted for both practice sessions that took him over the allocation of five that he is allowed for the season.
With him already pegged to the back of the grid, it is possible that Mercedes may choose to add further new parts to his allocations in final free practice on Saturday.
Mercedes has not specified in what areas its power unit has been improved, but both Hamilton and teammate Nico Rosberg have been given the new developments.
Mercedes customers have not got hold of the new parts yet, because their latest components were fitted as new at the German Grand Prix. But they will get the updates when they next get around to needing new parts.
The Belgium upgrade means that Mercedes has six development tokens left for the rest of the season, but is it unclear at this stage if it will elect to spend them.
Should it do so, the most likely place to introduce at upgrade would be when the next power units are due to come in to play, which is at the Japanese Grand Prix.
Power unit manufacturers have now used the following number of "tokens" prior to, and now after the start of, the 2016 season in accordance with Appendix 4 of the F1 Technical Regulations :
Ferrari 29 (3 remaining)
Honda 29 (3 remaining)
Mercedes 26 (6 remaining)
Renault 11 (21 remaining)