The follow changes have been made in v1.00:

1. Added support for WordPress v2.0-RC1 (see below for a screen shot)
2. Added timeout to XML-RPC calls.
3. Updated version number to 1.00.

Version 1.00 can be downloaded here: pjw_wp_version_monitor.1.00.zip

The follow minor changes have been made in v0.90:

1. Improved check for Tiger Admin Plugin – When detected alternate CSS is used for message display. Thanks to MarkJ for the new and improved CSS.
2. readme.txt included in the zip file with installation instructions.
3. Updated version number to 0.90.

The following new features have been added in v0.90:

1. Added support for wp-dash plugin with a builtin WordPress Version Check widget.
2. For advanced users who are installing this plugin on multiple blogs that they administer for others you can now enable email notification of new messages.

The email notification feature works in the following way. If you look in the source code of the plugin near the top you will see a line with:

var $admin_email = "";

If you put an email address in there then an email will be sent every time the message to be displayed changes.
e.g.

var $admin_email = "user@example.com";

The email received will look something like this:

Message from Version-Check/0.90
Running at http://example.com
Wordpress version is up to date.
Previous message was:
Wordpress version is out of date please upgrade.

Version 0.90 can be downloaded here: pjw_wp_version_monitor.0.90.zip

There is also now a page for WordPress Version Check which will always have the latest news.

Changes in v0.80:

1. Added GPL Licence Text.
2. Added check for Tiger Admin Plugin – When detected alternate CSS is used for message display.
3. Changed default CSS so that info level messages are displayed in grey rather than green.
4. Added version info to the IXR UserAgent – To enable tracking versions of the plugin in use.
5. Used action hooks to ensure only run update checks when in admin ui.
6. Updated version number to 0.80.

Version 0.80 can be downloaded here: pjw_wp_version_monitor.0.80.zip

1. Laziness.
2. They failed to notice the post on the dev blog in their wordpress dashboard.
3. They failed to notice the number of people blogging about having upgraded.
4. etc

To help alleviate this problem in the future I have crafted a simple wordpress plugin which takes a simple approach to get the users attention. Once activated the plugin checks an XML-RPC webservice for update news displaying a message at the top of every page in the wordpress admin user-interface. The plugin will check for an update to the message every 15 mins with an additional check being kicked off if the installed wordpress version changes so as to give instant feedback on upgrades.

The following images show three of the different responses returned by the current web-service and how they are displayed:

Response for 1.5.1.1

Response for 1.5.1.2

Response for 1.6-alpha-do-not-use

The plugin may be downloaded here: pjw_wp_version_monitor.php.0.75.zip
An updated version is now available see: http://blog.ftwr.co.uk/wordpress/wp-version-check/

Please leave any feedback and suggestions in the comments below.