Two easy ways to get the functionality using 8-bit strings, assuming
you've already set your locale properly:

(1) If your data is already an 8-bit string (i.e. isinstance(data,
str)), simply use data.upper() or data.lower()

(2) If your data is Unicode (i.e. isinstance(data, unicode)), convert to
8-bit using encode, apply upper/lower, and convert back to unicode. 
E.g. data.encode("Latin-1").upper().decode("Latin-1").  (I don't know
which encoding to use though -- So substitute whatever you have for
Latin-1, but don't use UTF-8.)

PS Martin: the 2.4/2.5 differences were caused by Cartman having hacked
his 2.4 installation to change the default encoding.