Apple's Mail Privacy Protection (MPP) is a new feature that allows Apple Mail users to hide information about when, where, and how they open emails. MPP prevents email senders from seeing a user's tracking details, including IP address, email opens and forwards, time stamps, geolocation, device type, browser or platform, and more. When toggled on, MPP hides the IP address of Apple Mail users, making it difficult for senders to track their activity. This change affects the way email marketers measure open rates, click-to-open ratios, and other metrics. With MPP, open rates will be inflated for recipients who receive emails on Apple Mail, as tracking pixels are triggered by the preloading process. Additionally, geolocation data and open times for Apple Mail users will be inaccurate, making it challenging to personalize content based on location. Email campaigns relying on opens may break or become unreliable due to the lack of accurate data. However, focusing on reliable metrics such as unsubscribes, bounces, and spam reports can help email marketers adapt to this change and improve their campaigns.