Have been using and benefitting from this app for a while, especially in dealing with junk mail (I like to DELETE it rather than trashing it, as I keep all my trash). Leopard Mail disables it on launch and advises the used to contact the developer, so perhaps the current version does work and Apple is concerned third-party plug-ins will make it look bad. Along with the death of Classic, another unwelcome loss of backward compatibility that makes me wonder whether I should have waited for 15.1, or not upgraded at all.