Based on the settings done by the admin, you will receive mails for the events listed below:
When a customer creates a ticket via email
When a new follow-up is added to a ticket
When a follow-up is edited
When a follow-up is deleted
When a ticket is reassigned
Mail to Previously assigned member
Mail to newly assigned member
When a staff-only follow-up is added/edited on a ticket
When a staff member subscribes to a ticket
Mail to Admin about subscription by a staff member
When a subscriber is removed from a ticket