Chronology
Although no dates were specified at the time, the 2006-7 series The Volgan War explicitly places that conflict in 2082-4, with the invasion of Western Europe in 1999 (from Invasion!) as backstory and considered to be World War 3 in the ABC timeline. This retcons out the Judge Dredd strip Hammerstein, which placed the ABC Warriors in Dredd's universe and showed Hammerstein involved in 2071's Battle of Armaggedon after the Volgan War and the Mars mission.
The adventures of the ABC Warriors in Nemesis Books 3 and 4 take place "thousands" of years in the future, with Earth renamed Termight, a quasi-mediaeval future society where the knowledge for making robots belongs to the Lost Age of Science. All robots who have lived thus far have become antiquated relics, forced to salvage spare parts from fallen colleagues to survive. Book 5 sees them travel forward billions of years in time to the end of the earth, where they first encounter the Monad. When the Warriors part company with Nemesis in Book 6, they travel back to a period slightly prior to Termight - the Terran Empire, a much more technologically orientated society - for their remaining post-Nemesis adventures.
(This does raise the question of a time paradox: technically, there are two versions of Hammerstein, Joe, Blackblood and Mongrol in existence from 'Black Hole' onwards - the original versions and their later counterparts who travelled back in time from the Termight era. It seems extremely unlikely that this paradox will ever be addressed.)
The Mars stories from Roadkill onwards seem to be set a couple of generations on from the original Mars stories - the Biol corporation is still a major player and Mars' civilisation is largely the same, though enough time has passed for some Martian races, such as the Humpies and Cyboons, to degenerate to a lower state of being. The ABC warriors' original Mars mission has passed into near-legendary status, with most believing the warriors to be long since dead before their return.
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