When a person updates their contact email address, they should be given the option to update their BBID as well.
At the very least, we should be able to change BBIDs via a CSV upload. We are going to users who do not have access to their old email accounts to retrieve passwords, and we will be forced to manually update them.
It is possible to update BBIDs in bulk through the Data Import tool (User management category and BBID username import type). We are considering how to streamline email updates when users change their BBID but don't have a planned path for that yet.
Ideally the BBID would automatically update when a user updates their email address in Core, but if that isn't possible, please allow for staff to put a message to this effect in the popup box that appears when a user edits their email address.