Please deactivate before upgrading, then re-activate the plugin.
The Collapsing Pages plugin creates a list of all pages and sub-pages, which can be expanded and collapsed dynamically, as you can see in the sidebar on this page. The main function is as a widget, but there is also an option to use it as a drop-down horizontal menu for basic page navigation, if you are using wordpress as a cms, as in the screenshot below:
Note that the dropdown functionality has been removed in version 0.3, and will be made into a separate plugin in the near future.
The plugin is hosted on the official wordpress repository at: http://wordpress.org/extend/plugins/collapsing-pages
If you have any questions, bug reports, or feature requests, please go to the forum
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