How does MPP affect open rate tracking?

MPP inflates open rates dramatically. Because Apple prefetches images for all emails delivered to MPP-enabled inboxes, tracking pixels fire automatically. An email that was never opened by a human still registers as opened in your analytics.

The impact depends on your audience composition. Lists with heavy Apple Mail usage (common in B2C, especially in the US) saw open rates jump 20-30 percentage points overnight when MPP rolled out. A list that previously showed 25% opens might suddenly report 50% or higher, but actual engagement hadn't changed.

Open rate became a ceiling metric rather than an engagement metric. You can see the maximum possible opens (emails delivered to functional inboxes), but you can't distinguish between real opens and prefetched ones for MPP users.

The tide rose, but not because more ships arrived. Smart marketers shifted focus to clicks, conversions, and other engagement signals that MPP doesn't affect.