Caused by: java.lang.IllegalStateException: Could not load plugin descriptor for existing plugin [novatusplugin.zip]. Was the plugin built before 2.0?

I have been trying to deploy my own plugin and I have followed all of the instructions properly I think. I am enclosing a copy of my plugin and I have the plugin-descriptor.properties file in the root of my zip and I still get the error, any help would be appreciated. I am trying to build this again 2.3.2

Thanks