1904?

Personally, I didn't find that leap bothering. "Ulysses" is too much of a universal story to anchor it to any precise moment. Even though it's particularly a novel about Dublin, it's also a novel about mankind on a more general level, and the story looks pretty convincing in the film, even without a precise temporal setting. Finally, the film is much more focused on the characters than on the city itself. If you're really pursuing the accurate reconstruction of the time for any reason, the newest adaptation ("Bloom") offers a fine image of the 1904 Dublin, but lacks the accuracy of direction and profound understanding of the text that this film has to offer.