Updates are not shown for plugins that have space(s) in the name displayed in the plugin page (and, by extension, plugins that do not have a display name that is exactly the same as the SVN directory name). Switching the spaces to dashes in the plugin's header information causes updates to register correctly again.
This problem could be solved in a number of ways:
- Add support for a new metadata tag for either the display name, or the repository name, so that the two values can differ. Specifying the latter is probably more backwards-compatible.
- Have either the client or the server normalize " " to "-".
- Force all the plugin writers to have their plugin names exactly match their depot names.
I'd really like to see the first option happen, but I don't know how much work it entails. In any case, the fact that this matchup has to happen should be documented somewhere, because it will break the update feature for an unknown number of plugins.
I've attached an HTTP request demonstrating this problem, checking against the In Series plugin (you can change In+Series to In-Series in the file to see the update info working correctly). Simply execute cat request.txt | nc api.wordpress.org 80 to see the results.