city upgrade

[franklin1000]

When do you upgrade a city? When you do, what happens?

[Roberbond]

When your population grow up to a certain level in that city. Your governor will warn you.

[franklin1000]

ty

[Falke]

ORIGINAL: franklin1000

When you do, what happens?

a) You can build higher level assets, these require city size>= Asset level
b) The city civilisation level drops because it is roughly QoL/City Size

[franklin1000]

that's what I was wondering
ty