Yeah—that. Really, it’s obviously just John Wagner having fun with his toys, but Dredd has compared to many other strips (*cough*constant Marvel/DC reboots*cough*) been fairly tight from a continuity standpoint. Looks like from the dates we have, this might need addressing in 2028, assuming 2000 AD still exists then, and assuming the editor at that point gives a crap about extreme nerds. (Strontium Dog states a massive nuclear war occurs in 2150. Dredd is currently set in 2143.)
Personally, I couldn’t give a rat’s arse about such connections. I see them as fun asides rather than anything to worry about—alt dimension shenanigans. After all, we don’t feel compelled to roll in Batman’s entire continuity into Dredd, and then by extension the entire DC universe (or at least one of them). Do we?