How does MPP affect open rate tracking?

You check your dashboard after a campaign send and see a 70% open rate. Before September 2021 that would've been a reason to celebrate. Now it might mean Apple's Mail Privacy Protection just pre-fetched your tracking pixel on behalf of every Apple Mail user on your list before any of them actually touched the email.

MPP is a privacy feature Apple launched with iOS 15 that automatically loads email content, including tracking pixels, the moment a message arrives in a supported inbox. Your ESP sees a pixel load and records an open. The reader may have deleted the message without ever seeing it. On lists where Apple Mail users make up 30% or more of subscribers, this inflates reported open rates by a wide margin and makes open-based engagement data unreliable.

What you can still trust is clicks. A click requires a human to tap or select a link, so click rate remains an accurate engagement signal in a post-MPP world. If you've been defining engaged subscribers as those who opened in the last 90 days, you'll want to rebuild that segment around clicks instead. "Clicked in the last 90 days" is the standard replacement, and it's a stricter filter that gives you a more honest picture of who's actually paying attention.

To see how exposed your list is, check your ESP's email client or device breakdown report. If click rate looks healthy relative to your old benchmarks, you're probably fine. If click rate is low but open rate is high, you're likely seeing MPP inflation. Automations triggered by "subscriber opened but didn't click" are the first things to audit, since those branches now fire for Apple Mail users regardless of real engagement.

The practical next step: pull your last three campaigns' click rates and compare them to your open rates. If the gap has widened noticeably since late 2021, MPP is affecting your data. Use click rate as your new primary engagement signal, and rebuild any suppression or re-engagement lists around it.