bbp_user_maybe_convert_pass()

function bbp_user_maybe_convert_pass() {

	// Bail if no username
	$username = !empty( $_POST['log'] ) ? $_POST['log'] : '';
	if ( empty( $username ) )
		return;

	global $wpdb;

	// Bail if no user password to convert
	$row = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM {$wpdb->users} INNER JOIN {$wpdb->usermeta} ON user_id = ID WHERE meta_key = '_bbp_class' AND user_login = '%s' LIMIT 1", $username ) );
	if ( empty( $row ) || is_wp_error( $row ) )
		return;

	// Setup admin (to include converter)
	require_once( bbpress()->includes_dir . 'admin/admin.php' );

	// Create the admin object
	bbp_admin();

	// Convert password
	require_once( bbpress()->admin->admin_dir . 'converter.php' );
	require_once( bbpress()->admin->admin_dir . 'converters/' . $row->meta_value . '.php' );

	// Create the converter
	$converter = bbp_new_converter( $row->meta_value );

	// Try to call the conversion method
	if ( is_a( $converter, 'BBP_Converter_Base' ) && method_exists( $converter, 'callback_pass' ) ) {
		$converter->callback_pass( $username, $_POST['pwd'] );
	}
}