Every staff receives email notifications for several activities on their help desk such as - the creation of a new ticket, the assignment of a ticket to them, the merging of two tickets etc.
Each staff can choose to opt in/out of these notifications, and enable or disable each particular notification for a specific category.
Here's how this can be done:
This will provide the option to enable or disable email notifications of tickets from specific categories.
To enable/disable a notification altogether, just select/deselect the check box next to the respective notification option.