Last month there was a
Faerun '68 thread about updating Forgotten Realms to a more modern time as inspired by the Blades '68 KS.
The big question is what do you want it to add to the game? Tech is the obvious one: guns, cars, trains, telephones, airplanes? What about themes for adventuring: espionage, Cold War, class war, or just more ancient ruins from the last magic apocalypse? Then how does tech and social advancement change the economics. A typical D&D commoner could make x GP of grown crops or crafted items. Now with a tractor or machine tools they can make 10x or 100x. Many things, such as magic items, that might have been limited to adventurers or nobles would now be common among the people. How much do you want tech to change things? One way to limit quick advancement and ease is to say the world doesn't have, or at least not as much, coal or oil. We take all that stored energy and how it was able to change our lives very much for granted.