I was working on the phone to reroute a trip in October to Buenos Aires. In resetting everything, I put in for an upgrade from Z to ON using Miles and Money (UA flies a 3-class 767 from EWR to EZE). The agent said why don't I use a GPU instead. I said I didn't think that was allowed. She said they received notice on May 1 that Z fares are now eligible for GPU upgrades to FC. I said go for it and since there was ON availability, the confirmation went through. Anyone else heard about this yet? The website language has not changed.