Upgrades

Upgrades allow you to improve and specialize your units, camps, bridges and cities. Each object has a limited number of upgrade slots which can be viewed and modified in the upgrades tab or the upgrades window. Similar to generals, upgrades have fixed attributes that are applied to their parent object. Upgrades cannot be transferred between objects, but they can be dismantled or removed. What upgrades are available for a given object is based on its native faction. Some upgrades have prerequisites that must be created first before they are unlocked. When purchased, these upgrades will replace their prerequisite in the same slot. Only one upgrade of each type is allowed for each object.

Officers
In the case of combat units, upgrades take the form of officers that can be promoted by spending the unit's experience points. Unlike generals, officers do not appear on the tactical map and they cannot be detached from the unit.

Units gain experience points for defeating enemies and as a reward for completing certain objectives. In the case of combat, experience is split between any unit involved in the fight. For objective rewards, the experience is split across all units belonging to your faction.

Most classes of officer have 4 ranks that must be promoted in order. Once an officer reached the highest rank, you have the option of spending further points to convert the officer to a general who behaves like any other general and can either remain attached to the unit or be separated and assigned a different command.

Some officer types, such as those who increase the size of the unit, require an ongoing salary that is added to the cost of the unit.

Buildings
Upgrades for cities, camps and bridges are called buildings and are constructed with wood. Most buildings also have an ongoing maintenance cost that is added to your faction's expenses.

Buildings take time to construct and will consume wood as construction progresses. As with other resources, buildings will attempt to draw wood from other cites along your supply lines if there is not enough locally. If you decide you need to use your wood for something else, you can pause building construction in the upgrade tab or upgrade window.

Camps, cities and bridges have a special upgrade slot for walls and only wall upgrades can use this slot.