Text file: Units.txt

How Used: Flag; add text UpgradeTo and the unit to upgrade to.

How it Works:: UpgradeTo allows for old units to be upgraded. In the text file you can repeat entries of UpgradeTo for later technologies. The game checks if the upgrade unit can be built in the city then checks how much gold you have. The price of gold is the shield cost of the new unit - the old unit shield multiplied by your governments RushUnitModifier?.

Game Function: If a unit is obsolete (no longer buildable) and you can build the next unit listed in UpgradeTo then when you sleep a unit in one of you cities that Unit will be upgraded to the next unit if you have enough gold for it. The flexibility of UpgradeUnit? also takes in account special units that are available if a good is required. So if you don't have the good then you can still build the old unit (works better than just obsoleting by advance). For example if tanks require oil and you don't have any then you can still build cavalry.

Mods Implemented: Civ3mod by E. Warriors to Swordsmen etc

Similar code: ObsoleteUnit

Implemented by: E as of Revision 571