Can you upgrade units in DS version?

[Some guy]

I've been looking around this site, and of course through my DS game, but I can't figure how to turn my Warriors into a Rifleman. Does the game not allow unit upgrades except through that one wonder (forget its name)?

 

[PiMan]

Entirely correct. That is the only way to upgrade.

 

[Mango Elephant]

leanardos workshop or if your a german