Honda has announced that all four Red Bull and Toro Rosso drivers will receive a new Spec 4-ICE in Russia, a move that will warrant grid penalties for both teams.
The changes are a strategic move by Honda destined to provide Red Bull's drivers with relatively fresh horsepower at the Japanese manufacturer's home race at Suzuka in two weeks' time.
Toro Rosso's Daniil Kvyat, who took on a new Spec 4 engine at Spa, will receive a complete new unit at Sochi and will therefore start his race on Sunday from the back of the grid.
Red Bull's Max Verstappen and Alex Albon, as well as Toro Rosso's Pierre Gasly, will only take on a new Internal Combustion Engine, meaning the three drivers will be set back five spots on the Russian Grand Prix grid.
Honda's progress this season is undeniable, but the manufacturer's development programme has also extended engine usage comfortably past the permitted limits.
While Mercedes and Ferrari drivers have used just three ICE elements so far this season, Verstappen is set to take on his fifth ICE year-to-date.