The 747-100Fs are being retired one by one already, the first being the 32 year old ex-Pan Am-Birds. There was a post a few weeks back about two being retired at the end of 2002, N681UP being one of them. But I don´t know until when the rest of these very old birds are leaving. All the ex-AA 747-123s are still going strong. And they´ve been built back in 1970.
In the last years UPS aquired 747-200Fs one by one. Maybe they keep doing that, but I could also see them being a possible buyer of older 747-400s for SF-modification later.
But there are definitely no published plans about what´s going on at UPS in this matter.
Btw, Evergreen is in the same situation, their average fleet-age is even higher.
UPS currently operates 16 747s, 9 -100s and 6 -200s. Actually the ex-AA -100s are being retired before the ex Pan Am -100s. N671UP and N674UP, both ex AA -100s were placed into storage at ROW last month. N527UP was returned to the lessor. The latest retirement plan that I heard was all the -100s would be gone by 2005, with the ex Pan Am planes being the last ones to go and the -200s being returned to the lessor when it's lease expires, with the four owned by UPS, (N520-23UP), being retired in 2007.
UPS is looking into replacements for the current fleet of 747s. Senior management has stated in a pilot group meeting a couple of months ago that UPS has narrowed the choices to 3 types, the 747-400F, A340-600F, 777-300F. The last two types do not exist yet. Management said they would like to have the new plane in service by 2007. The latest rumor, relayed by a management pilot, is that at least two management pilots went to Boeing and recieved 777 type ratings. This leads me to believe that the 777-300F is a very real possibility because there is no way UPS would send a couple of managers to get 777 type ratings just for the heck of it.