McLaren is the only Mercedes customer team without the new power unit specification at the British Grand Prix this weekend. Team CEO Zak Brown confirmed the decision stems from remaining mileage on the current engines.
Brown spoke during Friday's FIA press conference at Silverstone. He explained that McLaren must cycle through its existing engines before switching.
"We've got life left on our current engines, so we need to wait until we do an engine change," Brown said. Other Mercedes customers including Alpine and Williams have already adopted the reliability upgrade introduced by Mercedes in Austria.
Brown expects Lando Norris and Oscar Piastri to receive the new specification ahead of the Belgian Grand Prix at Spa-Francorchamps. The circuit's power demands make it a logical point for the change.