actually SMF was update from 1.0 to 1.1, which has quite a few other changes - and took 3 attempts to get right because it insisted on converting the forum from ISO-8859-1 to UTF-8 - which was a small problem because although previously the forum had been set to use ISO-8859-1, clients had been set to send as UTF-8 (which would be saved as sent) then to display the output as UTF-8, effectively meaning it was already UTF-8... took several attempts to figure out how to fix that (in the end i made it convert from UTF-8 to UTF-8... erm...)
the 2 hacks that were on the forum before are in SMF 1.1 as standard which should mean fewer chances of things breaking (less hacks = less for modifications to modify incorrectly), however for this update itself it is a major update so chances are something would have broken... have to wait and see what, the critical stuff seems fine (by the lack of "ahhh" posts)