I’m noticing the same thing on my 2.3 and 2.5 blogs and I’ve seen other threads on this. Yet to see any responses though…
Plugin update notification is not broken – it’s just not working the way is was working prior to 2.5 (or 2.3.?).
The Word Press code (that you have installed on your server) gathers the list of active plugins and sends a request to api.wordpress.org to compare your active plugin list with the plugins hosted on wordpress.org. The list that originates from your server contains the plugin name (from the plugin’s header) and the plugin version installed on your system. The wordpress.org server located the SVN directory (I don’t know how) and made the comparisons to determine if the plugin version had changed.
The method used for locating the correct SVN directory has been changed for some reason – now it appears that the api.wordpress.org attempts to locate the plugin’s SVN directory by looking for an SVN directory on the plugin host that is the hyphenated version of the plugin’s name.
Plugin Name: My Cool Plugin = SVN directory: my-cool-plugin
If the SVN directory can’t be located then it doesn’t recognize that the plugin may have been updated. Unfortunately, the previous criteria for plugin developers to take advantage of the feature was the plugin name in the readme.txt file had to match the plugin name in the plugin’s header – the SVN directory was not part of the equation from the developer’s viewpoint. SVN directories are assigned when you sign up and there is no mention of the directory name in any of the current documentation; WordPress.org took care of it.
Because some plugins happen to have a plugin name that matches their assigned SVN directory – you will get notifications if the plugin has been updated. For plugins whose names do not match their SVN directory you will not be notified if they have been updated. This is because the SVN directory can’t be located for the plugin.
Plugin Name: My Cool Plugin = SVN directory: cool-plugin-for-wp
This is a nasty problem because
1. It works for some plugins and not others
2. Most plugin developer’s probably don’t realize there is a problem
3. The request API was changed and plugin naming conventions to support the new change has not been documented for developers
4. Changes to the API were made that basically broke a previously working feature
