I have been making some changes to the website and removed a couple of old email address from the list in the website.
Does that stop them from getting updates and cancel their membership?
This is in the /members/ area as I notice one of my old email accounts still gets updates.
It certainly cancels their membership (so for example they can't view any pages that only have read permission for members).
However I believe there is currently a bug in that if someone has signed up for notifications on a group and then have their membership revoked, they still receive notifications.
I have started working on a fix for this, and will put it onto the site when it's done and tested.