This major release include some interesting updates, such as a redesigned admin interface and a new theme called “Twenty Eleven”. The primary focus on this update was however to make WordPress both faster and lighter. In order to accomplish that, the developers had to raise the system requirements from PHP 4.3 and MySQL 4.1.2 to PHP 5.2.4 och MySQL 5.

Among the other updates you will find:

• Redesigned post editor with fullscreen button
• Extended Admin bar
• No more IE6 support
• Incremental upgrades (=faster)

What’s new

• Fixed moderate security issue where a malicious Author-level user could gain further access to the site.
• Remove pingback/trackback blogroll whitelisting feature as it can easily be abused.
• See all updates

To upgrade, visit http://wordpress.org/download/ or update automatically from the Dashboard > Updates menu in your site’s admin area.

The following example will add a “Document date” field. Add this code to your functions.php file:

<?php
// Add new field to all document types, except images
function extended_meta_attachment_fields_to_edit($form_fields, $post) {
    if (substr($post->post_mime_type, 0, 5) != 'image') {
        $document_date = get_post_meta($post->ID, '_document_date', true);
        $form_fields['document_date'] = array(
            'value' => $document_date,
            'label' => __('Document date'),
            'helps' => __('Date when this document was published.'),
        );
    }
    return $form_fields;
}
add_filter('attachment_fields_to_edit', 'extended_meta_attachment_fields_to_edit', 10, 2);

// Save data from the field
function extended_meta_attachment_fields_to_save($post, $attachment) {
    if (isset($attachment['document_date'])) {
        if (empty($attachment['document_date'])) {
            delete_post_meta($post['ID'], '_document_date');
        } else {
            update_post_meta($post['ID'], '_document_date', $attachment['document_date']);
        }
    }
    return $post;
}
add_filter('attachment_fields_to_save', 'extended_meta_attachment_fields_to_save', 10, 2);
?>

Custom fields for attachments can accessed using get_post_meta (same way as for posts and pages). Here’s an example where we have extended the code from our previous post with the custom field value.

<?php
$attached_documents = get_children(array(
	'post_parent'    => get_the_ID(),
	'post_type'      => 'attachment',
	'numberposts'    => -1, // show all
	'post_status'    => null,
	'post_mime_type' => 'application/pdf,application/msword,application/vnd.ms-powerpoint,application/vnd.ms-excel,application/zip'
));
if (!empty($attached_documents)):
	echo '<ul>';
		foreach($attached_documents as $attached_document) {
			$document_url   = wp_get_attachment_url($attached_document->ID);
			$document_title = apply_filters('the_title',$attached_document->post_title);
			$document_date = get_post_meta($attached_document->ID, '_document_date', true);

			echo '<li><a href="' . $document_url . '" title="' . $document_title . '" target="_blank">' . $document_title . '</a>, ' . $document_date . '</li>';
		}
	echo '</ul>';
endif;
?>

<?php
$attached_documents = get_children(array(
	'post_parent'    => get_the_ID(),
	'post_type'      => 'attachment',
	'numberposts'    => -1, // show all
	'post_status'    => null,
	'post_mime_type' => 'application/pdf,application/msword,application/vnd.ms-powerpoint,application/vnd.ms-excel'
));
if (!empty($attached_documents)):
	echo '<ul>';
		foreach($attached_documents as $attached_document) {
			$document_url   = wp_get_attachment_url($attached_document->ID);
			$document_title = apply_filters('the_title',$attached_document->post_title);

			echo '<li><a href="' . $document_url . '" title="' . $document_title . '" target="_blank">' . $document_title . '</a></li>';
		}
	echo '</ul>';
endif;
?>

This example lists all PDF, Word, PowerPoint and Excel files. For more MIME types, check out w3school’s comprehensive list.

In a head tag:

<meta name="generator" content="WordPress 2.9.2" />

In a “generator” tag in your RSS feed:

<generator>http://wordpress.org/?v=2.9.2</generator>

To hide this information – just add the following lines to the functions.php file in your theme directory:

<?php
	/* Remove WordPress version */
	remove_action('wp_head', 'wp_generator');

	function remove_feed_generator() {
	return '';
	}
	add_filter('the_generator', 'remove_feed_generator');
?>

Why hide this information? Some versions of WordPress have included vulnerabilities in the past and will most probably do so in the future as well. By hiding your WordPress version you will make it a bit harder for a potential hacker to know which vulnerabilities to use.

Also, remember to keep both your WordPress installation and it’s plugins up-to-date!

Here’s an example on how to create a plugin that allows you to insert iframes using shortcodes. Regular iframe tags can be inserted via the HTML editor in WordPress, but the example below will give you a hint on what it can be used for.

<?php
/*
Plugin Name: Iframe Shortcode Plugin
Plugin URI: http://www.guidecloud.com/2010/07/14/writing-your-own-iframe-shortcode-plugin-for-wordpress/
Description: Add iframes to Posts and Pages within WordPress.
Author: GuideCloud.com
Version: 1.0
Author URI: http://www.guidecloud.com/
License: GPL2
*/

class guidecloud_iframe_shortcode {
    function shortcode($atts, $content=null) {
		extract(shortcode_atts(array(
			'url' 	=> '',
			'scrolling' 	=> 'no',
			'width' 	=> '100%',
			'height' 	=> '500',
			'frameborder' 	=> '0',
			'marginheight' 	=> '0',
		), $atts));

		if (empty($url)) return '<!-- Iframe: You did not enter a valid URL -->';

	return '<iframe src="'.$url.'" title="" scrolling="'.$scrolling.'" width="'.$width.'" height="'.$height.'" frameborder="'.$frameborder.'" marginheight="'.$marginheight.'"><a href="'.$url.'" target="_blank">'.$url.'</a></iframe>';
    }
}

add_shortcode('iframe', array('guidecloud_iframe_shortcode', 'shortcode'));
?>

Create a new file called iframe-shortcode.php, paste the code above and upload it to your wp-content/plugins/ directory. Go to “Plugins” in your WordPress administration and activate the plugin.

Once the plugin has been activated you can place iframe shortcodes, like the example below, into your WordPress posts.

[iframe url="http://www.linktoiframe.com/iframepage/" height="500" width="100%" scrolling="no" frameborder="0" marginheight="0"]

You can also download the plugin here:
WordPress Iframe Shortcode Plugin

More reading:

• Writing a plugin – WordPress Codex
• WordPres Shortcode API

Among the 1,217 bug fixes and feature enhancements you will find:

• Custom Post Types – no more need to hack posts or pages into something they’re not
• Merge between WordPress MU and regular WordPress – now available within the same version. More info here.
• Custom menus – create your own menu
• New default theme – Twenty Ten

Introducing WordPress 3.0 “Thelonious”

Thanks to everyone involved – you’ve done an amazing job!

There are a number of variations on this error message, some more descriptive than others. This solution will however only work when you just get ”Installation failed” as the error – nothing more, nothing less. In this case it was tested on a WordPress 2.8 to WordPress 2.8.4 upgrade with WordPress installed in the website’s root folder.

The solution

The FTP account, used for the automatic upgrades, did in this case have the WordPress installation folder as it’s root folder. By moving the FTP root up one level, above the WordPress installation folder. Example:

FTP root folder – before:
/home/domains/mydomain.com/public_html/

FTP root folder - after:
/home/domains/mydomain.com/

Your web host might be able to help you out if you can’t configure this using your control panel.

Happy upgrading!