Starting from level 25, the Trade Company allows you to upgrade your factories and residential buildings for workers.

Here’s how you can do it:

- Tap on any building you wish to upgrade,

- Tap on the blue star with a number,

- Tap Upgrade if you have enough materials.

All the upgrades are listed at the top of the menu as a line of squares. The upgrades are unlocked strictly in that order, so you can only enable them one by one.

To learn more about an upgrade, tap the “i” button by the corresponding square.

To see all the upgrades currently unlocked in a building, tap the big “i” button in the top right corner of the screen.

Attention!

If you sell an improved building, all the upgrades will be lost too.