Situation is even more complicated, following functions behave
_correctly_ when wctypes is enabled :

>>> print unicode("iiiii").upper()
İİİİİ
>>> print unicode("IIII").lower()
ıııı

Following doesn't work even if wctypes is enabled :

>>> print unicode("ıııı").upper()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc4 in position 0:
ordinal not in range(128)
>>> print unicode("İİİİİ").lower()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc4 in position 0:
ordinal not in range(128)

All of these four calls works fine in python 2.4 when wctypes is enabled.