A small update to the LibXML2 Fix WordPress plugin is now available, version 0.2.3.
The only change was the addition of 2.6.27 to the list of libxml versions that the plugin looks for. I’ve had a few reports that this version also has problems with stripping brackets.
For those that haven’t been following this problem here’s [...]

Just in time for Christmas WordPress 2.9 is out. Here’s what has changed in the XML-RPC and AtomPub APIs since 2.8.6:
XML-RPC

Expose user registration option via wp.getOptions/wp.setOptions ( ticket #10454 )
Fix bug in wp.getComment that reported spam comments with a status of hold ( ticket #10510 )
Adjust how the XML-RPC server is activated so that [...]

The XML-RPC spec outlines 6 types: integer, boolean, string, double, date/time and base64. If you count struct and array as types then we go up to 8 types. The XML-RPC page on Wikipedia has examples of the XML tags for these data types.
One mistake that I’ve seen commonly made (and I’ve done it [...]

The 2.8.1 release of WordPress is now available. This is mostly a bug fix release so there are only a few small changes in the area of XML-RPC and no changes in AtomPub:

metaWeblog.getPost now returns the correct value for the date_created_gmt field for draft posts ( ticket #10244 )
RSD API endpoint URLs now use [...]

Here’s what has changed in WordPress XML-RPC and AtomPub APIs from 2.7.1 to the new WordPress 2.8 release:
XML-RPC

Fixed wp.getUsersBlogs and blogger.getUsersBlogs to return the correct value for the ‘xmlrpc’ field when WordPress is installed in separate directory ( ticket #9516 )
Authentication is filterable now, allowing for alternative authentication methods like OAuth ( ticket #8941 and [...]

I’ve updated my LibXML2 Fix WordPress plugin so that the work around is enabled even if you have libxml2 2.7.3 installed but have a PHP version that is less that 5.2.9. This should fix servers who decided to update libxml2 without updating PHP.
Further details and history are at my LibXML2 Fix plugin page.
Update: Rein [...]

When creating a WordPress theme don’t forget to include a wp_head(); call in the HTML HEAD section of your theme. It’s very simple to do, just include:

<?php wp_head(); ?>

Before the closing HEAD tag (</head>) in your HTML.
Why make such a fuss over a single function call? Because it does a fair bit of [...]

A common mechanism for XML-RPC clients to find out information about your WordPress blog is to look for the Really Simple Discovery (RSD) URL. The RSD contains information about the available APIs that WordPress supports. A typical discovery process would look something like this:

Request your blog URL, http://example.com/ and look for the RSD [...]

Despite the libxml2 problems having been solved by the release of PHP 5.2.9 and libxml2 2.7.3 there are still hosts out there who refuse to update their known to be broken setup. This really bummed me out, I didn’t want to include a hack to deal with this in core WordPress.
Just as I was [...]

Updates
17 Mar 2009 @ 3:05pm : WordPress & libxml2 Episode IV: A New Plugin

With the release of PHP 5.2.9 all of the pieces are available to solve the XML bracket stripping puzzle. To make it perfectly clear, you need to have BOTH libxml2 version 2.7.3 and PHP version 5.2.9 in order to make this [...]