What’s New in WordPress 3.0 for Developers?

By Craig Buckler
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This article is outdated, check out what’s new in WordPress 4.6 here.

WordPress version 3.0 was released at the end of last week. It’s a little later than the intended May 1 release date, but WordPress is one of the most popular blogging and content management systems on the planet, so it was better to be late than cause issues for thousands of websites.

The update is the result of six months’ work by 218 dedicated contributors, culminating in 1,217 bug fixes and feature enhancements. So what can you expect from WordPress 3.0?

New Installer

WordPress has always been easy to install but it’s become even simpler. Few administrators will have to fiddle with the wp-config.php configuration file: all the MySQL settings can be specified within the installer panels now.

The new installer also allows you to specify the administrator ID and password. I suspect few people ever bothered to change it from the default “admin” in previous versions, so the facility to create your own ID will aid security.

New Interface

The WordPress 3.0 administration panels have received a polish. It’s hardly a radical change from version 2, but it’s lighter and feels slicker.

WordPress administration screen

There are few obvious changes to the interface until you reach the Appearance section.

New Default Theme

RIP Kubrick: you’ve served us well and many websites use you to this day. Kubrick has been replaced by “Twenty Ten,” a new theme that has built-in support for child themes, background alterations, header customization, and drop-down menus.

WordPress Twenty Ten theme

The theme’s look and widgets can be customized within the administration panel, so I expect many people will never venture beyond the Twenty Ten theme. For those that do, there’s a new “Install Themes” tab that allows you to search for templates by color, type, and features.

WordPress Multi-user

WordPress MU was a fork that allowed hundreds of blogs to run from a single installation; it has now been merged with the main version 3.0 application. It’s disabled by default, but can be switched on by adding the following line to your wp-config.php file:

define('WP_ALLOW_MULTISITE', true);

This could be the most important feature for web developers: you can create a number of websites using just one installation of WordPress. Updates are easier and hosting space is drastically reduced.

Custom Post Types

Pages and Posts were available in previous versions of WordPress:

  • Pages were normally used for static content such as About Us or Contact Us pages.
  • Posts would commonly be used for date-stamped news, articles, or blog posts.

WordPress 3.0 supports custom post types. For example, you could have a Product type that’s specifically used for items sold on your website. Product pages can then be treated separately; for example, have their own menu or search box.

Custom post types are configured using PHP rather than within the administration panels. Watch out for a full tutorial on SitePoint shortly.

Other Features

Where do I start? I suggest you visit the WordPress 3.0 Codex page for a comprehensive list.

Should you upgrade now?

I have no hesitation in recommending WordPress 3.0 for a new installation. But what if you’re upgrading from WordPress 2.x?

I’ve rarely experienced problems with the WordPress automated upgrade; it’s a quick one-click process that just works. However, my first attempt failed abysmally and I was left with a broken site. You should note that this was a test installation of 2.8.6 with lots of dodgy code and plugins, but you need to be wary: some themes and plugins are certain to break.

I would recommend updating a local test version of your site before attempting to upgrade the live server. Remember to back up your files and MySQL database, and you can’t go wrong.

If past experience is anything to go by, the WordPress team will almost certainly release 3.0.1 within a few weeks. If you’re especially nervous, you might be advised to wait a little longer …

Have you upgraded to WordPress 3.0? Did you experience any problems?

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  • Gargoyle

    I upgraded flawlessly to the Beta release a few weeks ago:- http://ga.rgoyle.com/blog – But my blog is pretty basic.

  • My just-launched WordPress 2.9 site upgraded to 3.0 perfectly. I’m a little more wary about upgrading my more plugin-heavy WordPress installations, though.

    • Ditto for me. I migrated to 3.0 from 2.9 effortlessly. I though use a few plugins, and even they could also be upgraded easily.

  • tiggsy

    I successfully updated my test site, then went on to update a further 12 live sites without incident.

  • Anonymous

    I upgraded and didn’t do all those things..I really should be diligent and a good developer (laziness) and back-up/test on local site before upgrading…

    My menu totally flipped out….I just finally got it figured out again…I had to make my theme/menu compatible with 3.0 but that Menu feature is noooice!


  • “I would recommend updating a local test version of your site before attempting to upgrade the live server.”
    This has always bothered me about WP. Setting up a local test version and populating it with content seems to produce an installation that is hard to move to a live server. The content gets filled with absolute URLs which break.
    Do we need to modify the local hosts file so that the live domain is served from localhost when testing (and then back again), or is there a better solution?

    • arts-multimedia

      You are right about local testing. I always use an online test environment in a password protected area. That works fine. I do the same with Joomla sites.

  • I upgraded from 2.9.2 to 3.0 with no problems.

  • Mr. Bo

    I backed everything up and upgraded from 2.9 to 3.0 with absolutely no problems. There are only four plugins and they needed updating along with themes but all that is in one place now. I like the changes I’ve seen so far.

  • alicem

    Upgraded all of my clients’ sites and blogs from WP 2.9.2 (I think was the last release) to 3.0 with no problems at all. I did test locally the sites which had a lot of plugins first just to make sure it didn’t break the site.

  • Victor

    “Watch out for a full tutorial on SitePoint shortly.”

    You know, “watch out” means to be careful. “watch for” would be more appropriate here.

  • arts-multimedia

    Thanks you for this sum up, it’s a big time saver for me, Craig. Can’t wait to test it.

    Kevin: I hear you. It’s indeed a big leap and probably some plugins will break. A test environment will tell you soon how bad the damage is, but you know the drill already, I suppose :-)

  • Alex

    Wait for 3.0.1. then more users test this version.

  • neil

    I upgraded two sites using the automatic installer (without hesitation :) ) and I didn’t experience any issue at all.

  • Wesley

    I recently started using WordPress a couple of weeks ago. Then I saw the notification at the top of the admin area that said upgrade to “3.0” I did and it took what seemed like mere seconds to be fully upgraded. I quickly used and adapated the 2010 theme to suit my needs. It looks sleek. I’ve only been using WordPress for about two weeks and am already considering updating my entire site. The fact that MU has been integrated into this new version is great as I run a website that contains a mini site on the same domain.

  • ndlela

    I spent the weekend upgrading a couple of the sites I manage for clients. All but one of the sites updated without any major hiccups. The site that did have problems kept hanging during the automatic upgrade and when I checked back with the site it was in “maintenance mode.” i kept getting the error “PHP Fatal error: Call to undefined function is_multisite() in … on line 505.” I ended up just upgrading manually which involved replacing all but the “wp-content” directory. I went back to the “admin” page and it walked me through whatever else I needed to do.

  • John Crumpton

    Due to the very easy new menu manager we decided to develop a client website in WordPress 3.0 while in beta, so was wary of upgrading each time to the latest build, but went without problem. Things moved around a bit, but no problem.

  • Ray

    I updated to 3.0 and now the only thing I can access is admin, completely blank url, no plugins, no additional themes, totally disappointed, would not recommend to ANYONE

  • Justin

    I upgraded from 2.0.1 to 3.0 without issue. Worked great!

  • robgolbeck

    I upgraded two of my personal sites from 2.9 to 3.0 and had no problems at all. However, I tried to upgrade one of my company’s blogs, also from 2.9, and got a fail message. Luckily it didn’t break the site, but I decided just leave it alone for now.

  • Christine Marsh

    Thank You for the post!

    I upgraded from 2.9 to 3.0 and everything is good except somehow my drop-down menus are now disabled. I am using a theme from Rocket Theme called Refraction. Has anyone got any ideas on what happened?

    Thank You!
    Christine Marsh Visionary Artist