After the destruction of the Armada, a mysterious artifact of Solon origin was discovered, leading to technological advancements and intense military buildup. It was not that well received, however, due to the lack of a new campaign in favor of refining and rebalancing gameplay. Because of contract issues (mainly of Wanadoo being sold), The Solon Heritage was not published in the USA. However, the Solon Heritage as well as Legions of Iron can now be obtained via a digital download from various online retailers.

Several changes compared to the original game: New gamemodes: Informant, where one side mainly has spies, while the other military units; Mess-up, where the wormholes move around randomly; Drill, where the only source of income is mining. New ships for all races: diplomatic ships which ferry RPs, money, research, etc. and residential bases which generate additional income. In addition, all races can build Solon ships which has superior firepower, armor, accuracy and firing range, offset by their insanely high upkeep (for example, a cruiser-class Solon Leech costs as much as five Cruisers) and unique vulnerability: destroying the communication center required for building these ships results in all Solon units owned by that player detonating. New race-specific units: Human: dropships wreak major havoc on planets and self-destructing satellites surprising the enemy. Kariak: disintegrator satellites weaken enemy ships while virus ships convert/destroy them. Darzok: kamikaze ships and special satellites whose detection range span through an entire system.