UTF8 conversion differences from v8.1.3 to v8.1.4

Hi,

Can anyone help me understand why converting the NULL code point (0000)
from UTF8 to ISO8859_1 is no longer legal in v8.1.4?  The conversion
proc
(backend/utils/mb/conversion_procs/utf8_and_iso8859_1/utf8_and_iso8859_1.c)
changed considerably between 8.1.3 and 8.1.4.  The utf8_to_iso8859_1
conversion function now goes out of its way to reject this code point
specifically, even though it is valid in both character sets.

We have some JDBC code which passes "\000" as a substitution parameter
for a PreparedStatement.  It worked in the last version, but it now
fails at the server with a ERRCODE_CHARACTER_NOT_IN_REPERTOIRE error.

Thanks in advance for any assistance.

Regards,
Eric Faulhaber