Greetings Iterable Community,

Due to the recent changes from Apple Mail Privacy Protection feature, released as part of their iOS 15 on September 20th, 2021, open rates for end users using iOS 15 will no longer be a reliable benchmark for measuring engagement. This is due to Apple obfuscating open metrics by generating an open regardless of a user’s activity to help improve protect user’s privacy.   

As a result, Send Time Optimization (STO) will be impacted as email open data is incorporated into our AI machine learning modeling to make predictions. To prevent customer’s end user’s open rates from being over inflated and retain the accuracy of our STO predictions, we will be filtering  ‘userAgent == Mozilla/5.0’ from STO predictions  for email campaigns and removing any false-positive opens matching this user agent dating back to September 1st, 2021. 

To summarize, to retain the accuracy of send time predictions and correct over inflation of open rates, the user agent ‘Mozilla/5.0’ for iOS 15 will be removed from our STO predictions. 

To learn more about these changes, please visit our release notes.