The latest and final versions 1.6, 2.1, and 3.1. No more patches will be released.
Then I don't understand this phrase:
What's wrong with version 3.1? It's time to stop using 1.6 and 2.1, because even the campaigns from those versions can be played through 3.1.
Is it possible to somehow connect the campaigns from the base game and "Hammers of Fate" to the 3.1 "Tribes of the East" version?