"Willy-Bas Loos" <willybas@gmail.com> writes:
> I've noticed that postgresql 8.1.0 can cast a boolean to text, but version
> 8.1.5 CAN'T.
Better check again --- there has never been a standard cast from bool to
text. Sure you didn't install a custom one in your 8.1.0 database?
regards, tom lane