Mail Privacy Protection (MPP) is an update in Apple iOS 15. It enables users to make it harder for email senders to follow their marketing activity.
This includes masking of IP addresses so that email senders do not know a recipient’s location. It also includes pre-loading content in an email. This means that email senders do not know if an email was opened.
Since iOS 15 was released, Apple Mail users now have the option to turn on Mail Privacy Protection. And they’re prompted to do so with a message.
If users select to protect their mail activity, what this essentially does is affect open tracking in an email. And it gives control to email recipients as to whether their email opens are tracked.