Atanu Roy, et al., "State of the Mart: Fast Forward," Computers Today, July 15, 2000
—"USSR — Machine Building," BBC Summary of World Broadcasts, November 28, 1979
This redundancy may explain why upgradation isn't in any dictionary (at least those that I have, including the OED 2; if you see it in a dictionary, let me know). However, a case can be made that it should be in the dictionaries because the word is both old and popular.
For evidence of its longevity, I managed to track it back to at least the above citation from 1979.
For evidence of its popularity, I checked through the Lexis-Nexis database of newspapers, magazines, and other media and found thousands of citations. However, the pattern of these citations is interesting. There were only 72 from 1979 to 1989. Then the numbers look like this:
1990 - 13 1991 - 10 1992 - 31 1993 - 46 1994 - 55 1995 - 44 1996 - 77 1997 - 483 1998 - 908 1999 - 853 2000 - 1,028As you can see, for some reason usage of the word exploded in 1997 - 1998 and has continued apace. So if upgradation isn't in any dictionary, it's likely because its popularity is relatively recent.