In addition to levelling up your buildings in the stadium complex you can purchase several upgrades that give you additional advantages and a cool new look.
With the upgrades you can for example boost your stadium capacity, or get a bonus on your training.
To purchase upgrades you can either use coupons that are available in the shop when the items are first introduced, or you can buy them at any time direclty in the Stadium complex by opening the upgrades tab. The upgrade can be activated and deactivated at any time, you can also change the design back to the standard building design. However, the added bonuses are only active when the upgrade is active.
It is possible to activate several upgrades for one building at the same time to receive all bonuses simultaneously. The upgrades stay active when your regular building is expanded, and all benefits are added to the standard benefits you receive from the buildings themselfes.
But careful: Some of the upgrades expire after a set time and have to be repurchased to keep the benefits.
Some of the upgrades are based on actual teams, their designs also resembles the actual design as the real teams have them. Those items might not be available for purchase indefinately!
Note: If your club and its progress gets deleted because of the inactivity of your account, all stadium upgrades that you've had will be removed as well.