Like genetic engineering: there's no mention really in classic Traveller, but if we state it has been so commonplace that nobody mentions it, like anitbiotics, a dragon is slain. My take is that genengineering would have to have been widespread, not to make super brainy people or guys with giant pecs, just to make frail old humaniti actually be able to survive for lengths of time in zero g, or not catch nasty diseases when they colonisie a new world, or even just visit one. The equivalent of malaria meds for visits to the tropics.
Lifespans should increase also. We're already well ahead of 3 score years and 10. Maybe 120 should be the normalised lifespan for healthy folk in the 3I.
This is pretty much how I see it. One other advantage of not mentioning specific bits of technology is that the game won't age as quickly. Nothing ages a game as quickly as mentioning specific storage capacities for computers, as just one example.