Check what file you have via version number... while you at it check if it is compressed or not
Download all necessary update files one by one ( ^ compressed or not !!! ) for instance you have v 71 then download v 73 UO v 75 UO v 77 UO v 79 UO v 81 UO
Do them one by one to the v 71 ( extract the UO archive and merge the www folder to the main one... repeat with higher versions if done )
Guess this is all there is to it... when you are finished (
and it works properly ) you can rename the original file to the latest edition number and you are done !
It looks something but it is easy as pie... practice it a couple of times and you will eventually master it !