Worked for a little bit but no longer works right!

I was using this plugin for quite awhile. But in the past couple months this plugin has been causing all sorts of problems. When you duplicate a product that has customers waiting for it to come back in stock and you publish the duplicated product you get a 500 error every time. I don’t believe it is even notifying anyone anymore and traffic isn’t increasing like it used to when products come back into stock. Hope the developer decides to update the application.