Per l'esigenza E (invasione ed occupazione Jugoslavia) verrà aggiunto un terzo reggimento cavalleria alle divisioni: Il Nizza (1) alla 1a divisione, il Piemonte (2) alla 2a, il Genova (4) alla 3a. Il 6° e il 3° Bersaglieri dopo una breve parentesi in Jugoslavia saranno destinati alla Russia mentre l'11° perde un battaglione.

For Esigenza E (as the Yugoslavian invasion was designated) the Fast Divisions received a new, revised organization. The most important changes were:
 – only one horse artillery battalion instead of a mixed artillery regiment;
 – a drastic reduction of services, most of which were now horse drawn;
 – a third regiment of horsed cavalry was allotted;
 – a third bicycle battalion was added to the Bersaglieri regiment (although this was dropped only four months later).