This is a  Plus Add On.

Plus Add Ons are included in all Plus or higher premium membership plans.

A Beta Release means that while the plugin is active and stable, it is not fully supported and should be used with caution in a production environment. While the functionality may work well with the core PMPro plugin, most of our Add Ons are not compatible with multiple memberships per user. We are working to update the documentation pages of Add Ons listed in this site to reflect current compatibility or plans to develop compatibility.

In particular, almost all of the Add Ons that adjust the checkout process, membership pricing, user subscriptions, or perform actions when users change membership levels will NOT currently work as you might expect with this plugin active.

This work will take one to two years at least. So please feel free to use the MMPU Add On in the meantime, but also take a look at the workarounds in this article which often work as well or better than using the Add On.