How to upgrade the arms of the heroes of the Three Kingdoms?

Infantry, cavalry, Gong Bing and thieves are upgraded in three stages:

Junior infantry is called short soldiers, short soldiers above 15 are upgraded to long soldiers after using long guns, and long soldiers above 30 are upgraded to chariots after using infantry vehicles;

Junior cavalry is called light cavalry, light cavalry above 15 is upgraded to heavy cavalry after stirrup, and heavy cavalry above 30 is upgraded to guards after stirrup;

Gong Bing in junior year is called Gong Bing, Gong Bing with 15 or more is upgraded to crossbowmen after using crossbows, and crossbowmen with more than 30% is upgraded to catapult after using catapults;

A junior thief is called a mountain thief. /kloc-More than 0/5 mountain thieves upgrade to evil thieves after using rogue spirit, and more than 30 evil thieves upgrade to righteous thieves after using chivalrous spirit.