Provide External Users with a notification tab where external users receive notifications from changes on the issues they are subscribed to on their dashboard.
At the moment external users are updated via email notifications exclusively.

The implemented solution doesn't save anything meaningful in the db other than field/attachment/user id. There’s no efficient way to display all of the notifications the same as they’re displayed in an email because we can’t store the change information, and most changelog endpoints are paginated and don't provide an option to search for a specific one.

Admin can select notification mode in global settings → notifications