BUG #5221: errors converting string to utf8

The following bug has been logged online:

Bug reference: 5221
Logged by: DM
Email address: dmedri(at)ciseonweb(dot)it
PostgreSQL version: 8.2 / 8.4
Operating system: linux ubuntu 9.10
Description: errors converting string to utf8
Details:

I'm using 2 version of pg (8.2, 8.4).

On 8.2:

select convert('Vall\xe9e','LATIN1','UTF8');

convert this string without any kind of error.

On 8.4:

select convert('Vall\xe9e','LATIN1','UTF8');

i receive these messages:

WARNING: nonstandard use of escape in a string literal
RIGA 1: select convert('Vall\xe9e','LATIN1','UTF8');
^
HINT: Use the escape string syntax for escapes, e.g., E'\r\n'.
ERROR: invalid byte sequence for encoding "UTF8": 0xe965
HINT: This error can also happen if the byte sequence does not match the
encoding expected by the server, which is controlled by "client_encoding".

client charset: utf8
server charset: utf8