There is not, and as far as I have inferred from dev talk, will probably never be a set date for AF0. There have, as you say, been multiple attempts to guesstimate an approximate time for when the Fall occured. Some of the things that went into this; The map of the solar system in the core rulebook features an alignment that only occurs every 70 years or so, or something like that. I believe this is where the 2130 number comes from. Edit :- 2146, and every ~90 years. This date also matches up with Uranus' south pole being in spring. Anything less than 2070 doesn't make sense as per the timeline in the core rulebook. BF60+ features space ladders, manned Lunar and Martian stations, and human intelligent dumb AI technology. There is the occasional concrete date scattered throughout the books. Gatecrashing features a woman killed in the Fall who was born in 1983. She could have been on the older sides of life when she died, but age treatments only became available to the super wealthy between BF60-40. This puts a limit on how far into the future we can go. I personally tend to go with 2130-2170. Actually I tend not to care, it doesn't influence my game. But when researching fun potential technology to add to my games as mcguffins, that is the window I use.