Why Audi and Ferrari can already upgrade their F1 engines despite ADUO delay

What exactly is causing the delay?
All Formula 1 manufacturers were informed of the initial results of the first ADUO (Additional Development and Upgrade Opportunities) period during the Monaco Grand Prix weekend and therefore know where they stand, subject to the additional check. That extra verification is taking place at the insistence of Red Bull-Ford Powertrains.
The newcomer was ...Keep reading