backwards compatibility problem

Hi all,

I was trying to upgrade the postgres JDBC driver I was using due to the
fix for supporting high-unicode characters.
I was using before the file:
postgresql-8.1dev-400.jdbc3.jar
and upgraded to:
postgresql-8.1-405.jdbc3.jar

The new one fixes indeed the high-unicode character support, but it
breaks other code we have...

Specifically, with the former driver the following query would work:

select ? - '1 day'::interval

where the parameter is set to a timestamp value (either via setTimestamp
or setObject without specifying the type, the result is the same).

With the new driver the same code results in:
ERROR: invalid input syntax for type interval: "2006-05-10
18:15:47.679000 +0200"

Casting the ? sign to timestamp in the query works here (tested), but I
wonder why this was working in the older driver and stopped working with
the newer. AFAIK the protocol did not change and strict typing was
required already with the old driver, so how come that got it right and
the new one does not ?

Thanks,
Csaba.