Prussian regulations were already changed in 1809, with an Instruction zum Exerciren der Infanterie, of 30 pages, published in Königsberg on 16th July 1809.
There, p. 20, the king ordered:
All the manners which have been formerly in use to form the square [Quarré] are abolished. Instead of them,at any time, a massed battalion [Bataillons-Masse] is used.
The description which follows, of how to form this square, is basically identical to the one of 1812.