Once your Add-ons are built you can upgrade their level to increase the power of their Abilities and Passive Bonuses even further. The Upgrade process requires food, petroleum, alloys, composites and the special Graphene resource. Graphene is a unique and very rare resource that can be collected from some Missions or can be acquired with Gold by selecting More and choosing a Pack that suits your development needs.
The Upgrades themselves can majorly affect the two main Add-on benefits - the Ability and the Passive Bonus. Upgrades will provide bonus to a single benefit, such as Ability Duration or multiple benefits like Ability Cooldown reduction, passive bonus increase and an increase in the ability's effect duration. The Add-on Upgrade interface displays all information about bonuses that will increase on the next level. Additionally, the "Ability" keyword will be shown in the Upgrade command interface, indicating that the effect gained from a specific upgrade relates to the ability.