The plugin protocol name is cached by the Indigo Server and there is not currently a method to clear that cache. However, if you open the device dialog, change the device to a different plugin, change it back, then OK out of the dialog it will be recalculated (I think).
Note the protocol name being old or stale isn't a huge issue since that name is just used in the UI and not used internally to look up the owner of the plugin. Maybe a bit confusing for users, but only for those already using the plugin and early adopters are normally pretty understanding.