After I uploaded my blog from 2.3.3 to 2.5.1 I see the unicode (bengali characters) are not showing. instead i see something like an ascii mess. the english posts are of course ok.
the unicode setting in wp admin is utf - 8 as it always was. same for mysql db collation.
the unicode characters are not showing not only on the blog but also in the admin interface.
This usually happens when during the upgrade you over-write or change the wp-config.php file. Older versions did not have the charset and collation lines... (anyway it would have been useless for older MySQL versions), so introducing them later = messes up everything.
Was this an automated upgrade via Fantastico?
No it was a manual upgrade. But yes, I changed the wp-config.php replacing the old one with the new. This I did to enable the secret key feature.
These are the lines in my wp-config.php
define('DB_CHARSET', 'utf8');
define('DB_COLLATE', '');