About upgrades

[BetterBear]

What is the code if I wanted a building to be built, but it must have another building upgraded first?

[PrathamK]

Requirements tag might be what you need, I don't know amuch about it.

[CommanderABab]

The building that needs to be built would need to set a variable when upgraded. The new building would require in a condition that that variable be set. Or possibly just check if the upgrade exists.