The email notifications that you enable on your account are automatically sent to the customers when an event occurs. However, you might want to avoid sending email to the customer if you are performing an action on a subscription that you do not want to customer to be notified about, such as regenerating an incorrectly generated invoice.
Though you cannot turn off email notifications for a specific customer, here are the steps you can follow to get this done.
Navigate to Customers > Select the specific customer and click on "Change Customer Details"(on the right panel). Screenshot below.
Here you can remove/modify the email address and click "Update Customer". (This is to ensure no email notifications are sent to that customer).
After you perform the desired changes to the subscription, make sure to update the actual email address of the customer.
This process is applicable to V1 & V2 email notifications.
If you want to restrict sending emails to multiple customers, you can perform a Bulk Operation to change multiple customer email addresses in one go. Here’s more on Bulk Operations.