upgrades

[planecrazy]

i must be missing something. when i try to upgrade my catapults to cannon i get a message that basically says "we have no catapults that can be upgraded" . i'm building cannon and i have the cash to pay for the upgrades ... what am i missing ??

[Skanky Burns]

You need to have your catapults in a city with
Barracks
and the correct resource(s) available.

If you are building a cannon already, then the resources should be ok, but make sure that you have barracks in the city too