I have a solution which uses a number of plugins. If I create a new version of those plugins and reregister them through the plugin registration tool in my development environment then everything is fine locally. If I then deploy that solution to a site which has an existing version of the solution then rather than replace the sdk message processing points it creates duplicate entries and no plug in code runs.
What is going wrong here? Is there a specific way in which I should update a plugin in a solution?