Troops upgrading
Was wondering if anyone really knows how this works. If I make a spearman when I get the tech and then choose for them to upgrade when the next better spear or armor comes out, I do see when I get leather armor the option to upgrade them. However, when I get boar spear it doesnt seem like they will upgrade. Im also wondering will I be able to upgrade Spearman all the way to end game wps and armor if I edit the current spearman that I have and keep selecting the upgrade options? And if so, will this overwrite my lower lvl spearman so that they wont appear in my next game when I start reseraching techs again?
I hope this doesnt sound too noobish to ask, but I just cant seem to figure it out with my units that I make. I can upgrade them once, but then when the next tech comes I cant...so im just not sure if I need to keep editing my units to upgrade before I get the next tech or if I can upgrade them once then done. Thanks all!