The Download:
Mail Privacy Protection

Mail Privacy Protection (MPP)

Strategies to update list hygiene practices and measure the success of future email campaigns


Apple’s recent iOS 15 update included the addition of MPP, which hides recipients’ IP addresses and prevents the sender from learning if the message was opened. Due to the large number of users opting-in and MPP syncing across all linked Apple devices, open rate is no longer a reliable measure for email performance or engagement.

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Percentage of Avalon clients’ subscribers who opened emails using the iOS mail app in Fall 2021. With more subscribers reading their emails on Mac computers, the number of recipients who don’t share their contact information is likely higher.

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Percentage of combined email opens by subscribers using Apple mail applications.
Source: 2021 Litmus study

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Ratio of Apple users who have adopted iOS 15 as of June 2022.
Source: Mixpanel Trends


Response rates and conversion rates ultimately remain the greatest indicators in determining the efficacy of a fundraising email’s content.


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Try These Tactics!
  • Adjust unengaged rule strategies to maintain list hygiene. A subscriber could be considered unengaged if:
    • They haven’t clicked on any of your emails within a certain time frame
    • They’ve had a high number of hard bounces
    • They didn’t convert to a donor within a certain time
  • Focus on response rate optimization. Design, content, and overall presentation of the call-to-action are just a few of the elements that can be constantly tested and refined to optimize donations.
  • Monitor other email metrics. Bounce rates and unsubscribes, for example, will play an increased role in measuring email performance and email list quality in this new environment. Click-through rates will also help gauge how email recipients are engaging with email content.
  • Supplement A/B testing with subject line scoring. Many online assessment tools grade potential subjects lines by word length, use of numbers, sense of urgency, and other factors. Some free online subjects tools are: