I should of probably specified that this is in relation to the password plugin that roundcube has.
I'm trying to make sure the passwords sync up with postfixadmin, the utility I use to manage my email accounts.
so, I changed the encryption type to mysql_encrypt. I then set the following in the password config.inc.php file:
$rcmail_config['password_query'] = 'UPDATE mailbox SET password=%c WHERE username=%u LIMIT 1';
so the password resets fine in roundcube, but it doesn't sync up properly to postfixadmin. once the password is changed in roundcube, it basically kills the old and new password for that email address for postfixadmin.