Unfortunately I am not maintaining this plugin any more. There are too many WordPress membership plugins for me to maintain a separate plugin for integrating each of them with Discourse. Instead, I have added some API functions to the WP Discourse plugin that can be used for integrating Discourse with various membership plugins. The API functions are outlined here: Manage group membership in Discourse with WP Discourse SSO.
To use the functions with a membership plugin requires writing some custom code.