For each post, author can choose which category is used in permalink.
If you have Dmytro's sCategory Permalink plugin installed, first deactivate it. Hikari Category Permalink doesn't conflict with the legacy plugin, but I don't recommend keeping both activated.
Once you are ready to install, you can use the built in installer and upgrader, or you can install the plugin manually.
/wp-content/pluginsfolder. Make sure the plugin has its own folder (for exemple
%category%tag. For an exemple, you can use
If you have to upgrade manually, simply delete
hikari-category-permalink folder and follow installation steps again.
If you are using Dmytro's sCategory Permalink plugin, just deactivate it and activate Hikari Category Permalink.
And once the upgrade is done, if you are using WordPress 3.0 or above, go to Settings > Permalink and replace legacy
%scategory% tag to stantard
To uninstall just deactivate the plugin, or delete its folder.
There's no wp_options option stored, posts category permalinks are stored as postmeta. Currently there's no automatic way to delete these postmeta if you don't need them anymore, this feature will be added in a future release.