Docks Upgrade is the upgrade for Imperial Docks to upgrade that dock to tier two. They must be upgraded PER DOCK and must be upgraded again if the Dock is destroyed. This upgrade must be purchased in order to upgrade to tier 3 (Docks Breakthrough).
Units Unlocked at Docks Upgrade
The following units requiers the Docks to be upgraded before they can be buiilt.
- Naginata Cruisier