We're currently looking into a mail delivery issue in the Email Campaigns feature and in order to avoid sending thousands of people test emails we went ahead and updated the sf_subscriber table changing all email addresses to an internal email address.
We confirmed this change by navigating to Subscribers under the Email Campaigns menu. (All subscriber email addresses had been changed)
Using Smtp4Dev we then set about Creating and Sending an Issue to 5 users. What we didn't expect to find was that the Issue would have gone out to the subscribers and their original email addresses.
Using a text search tool that searches all tables in a database for matching text values we found duplicate subscriber records in the sf_notif_subscribers. Sadly, using the Sitefinity Backend to change one of the subscribers does NOT update this table, so we're confused now about the purpose of these two tables.
What are they for and how is the data in them managed?