What’s mail privacy protection?

Apple declared a new policy that stops email senders from collecting some critical data about their recipients. Known as MPP (Apple Mail Privacy Protection), the iOS 15 privacy feature is expected to be launched this fall, around September – November 2021.

The data that will be blocked and become no longer available for email marketers to measure and assess deliverability is the open rate. Apple will block invisible pixels used to gather open rates data from recipients and mask the IP addresses so this type of data can no longer be tied to their online activity or used to determine their location. This law will affect all subscribers using Apple’s Mail App.

Why was open rate critical for email senders?

Email marketers measure open rates to discover if their emails are getting delivered in the recipient’s spam folder, segmented contacts, or finding out the most efficient days and times for sending emails to build out the specified automation based on this trigger.

How does open rate work?

An open rate is measured whenever the invisible pixel is uploaded at the bottom of the page. Included is the circumstance where anti-spam filters check the content for compliance, safety, or when an email provider preloads the images to show faster in front of subscribers once they open the email.

Why is Apple going to apply the Mail Privacy Protection?

With the removal of the open rate from Apple’s Mail App, the advantage for recipients is they will have the ability to control what data marketers collect about them.

Since the open rate is a vanity metric that doesn’t determine the accuracy or success of your email campaigns, your marketing team will have the ability to focus on more realistic metrics like click-through rates, conversions, unsubscribes, spam reports, revenue and list growth.

Although email provides a personalized interaction at scale, there are other forms of communication that your audience engages with like SMS, and web push notifications, pop-ups, etc. These interaction points are helpful to enable email marketers the ability to segment, optimize and build automated funnels to help align with the buyer’s journey that contributes to open rates.

Once you have established trust with your audience based on the forms or questions they have submitted, you have the legal right to respond with how your offering can help rescue them from the current state they are in and give them peace of mind knowing they are in good hands with your business.

How will Mail Privacy Protection (MPP) impact your email marketing?

MPP can have an impact over several elements used in your email marketing strategy:

  1. Performance metrics
  2. List segmentation and list hygiene strategies
  3. Send time optimization
  4. Live content in email

1. Performance metrics

Apple stated that the Mail Privacy Protection automatically preloads all images without the user viewing the email, which would show the open rates to be closer to 100%. Included will be all email addresses on the iOS mail app, but are not limited to Gmail, Yahoo, Outlook and other business email addresses.

This type of impact in the email community will affect the performance metrics due to the open caching used by the iOS mail app. Marketers won’t be able to distinguish real opens from false opens.

2. List segmentation and list hygiene strategies

Open rates have been an essential metric used for list segmentation and list hygiene. Once this feature is blocked by Apple, email marketers need to work harder to avoid using illegal sending practices.

Segmenting lists and maintaining proper list hygiene will still be required to confirm deliverability. Marketers need to shift their focus on other high-priority metrics such as click-throughs, conversions, bounce rates, unsubscribes and engagement with other automated messages like SMS and web push notifications.

A good school of thought would be to measure all open rate data using other metrics for backtesting and building new segments once the mail privacy policy update is in place.

3. Send time optimization

Since send time optimization relies heavily on open rates to detect the appropriate time for sending an email, it will become unfruitful when it is blocked by iOS.

A simple alternative would be to rely on other metrics like clicks or conversions to gather any historical data for backtesting new models.

4. Live content in email

Live or real-time content is classified as “dynamic,” which opens and changes based on where the message is opened. Since Apple primarily caches the images, any live content would be broken from this update.

Subscribers using the iOS Mail App will no longer be able to tap into live content, leaving marketers to rely on the customer data they have at the specified send time to personalize their images.

For mail clients supporting accelerated mobile pages (AMP) such as the Gmail app, senders should use AMP and send-time content as an alternative for clients not using AMP like the Mail App.

What should marketers do to cope with MPP?

1. Determine the percentage of subscribers using the apple's email client

Since the new policy affects subscribers via Apple’s Mail Client, focusing on this segmented audience to engage with your emails allows you to determine the outcome of MPP on your email marketing strategy. The greater the portion of this segment, the higher the impact.

2. Find out how dependant your email program is with real-time content

As Apple caches images, real-time content will become ineffective for recipients and convert into static content once they are cached. Therefore, dynamic blocks like countdowns in emails, which are used to induce urgency for contacts to take action for webinar registrations, eCommerce purchases and ebook downloads, require marketers to think of an alternative.

Before MPP takes place, a good strategy is to A/B test two variants of an email, one with a countdown and another without, observe the impact when changing that element and look for something else that would best replace it.

Although MPP won’t impact clients having iPhones and using other email clients like Gmail or Outlook, a significant part of them are likely using the native iOS Mail App.

3. Reconsider your KPIs

Since open rates are a vanity metric that marketers cannot possibly rely on solely to measure their email marketing success, it shouldn’t be a surprise when MPP takes place. Other KPIs are more critical such as (CTR) click-through rate.

(CTOR) click-to-open rate is a metric that has risen in importance in recent years and is calculated by dividing the total unique clicks by the unique opens. Although senders generally prefer to use CTOR metric more than CTR (Unique click rates/ Non-bounces send quantity), the MPP will also make CTOR less or even entirely useless. Thus, email marketers need to move back to the CTR metric.


Marketers who think big and have all their metrics well-defined and measured properly shouldn’t worry about MPP. Since the open rate is a vanity metric and not considered accurate data based on which the success of an email campaign is solely determined, email senders need to shift their focus onto actionable metrics like CTR, conversions and list growth over time. They should be mindful of what steps can be taken to prepare for this feature being rolled out.