I would like to know if that would be possible to for a client to upgrade from an expired plan?
It does not seems to be possible currently.
This would be a great addition as a lot of users that renew their plans for new features for example. And that's a basic feature for a membership component
Previously we had disabled the renewal plugin and override with our own plugin to do that, but currently it seems to be in the component core so can you point me in the right direction to do that?