iOS 15 Adds Mail Privacy Protection and Private Relay

What Changed

Apple announced the features at WWDC in June 2021, and they shipped with iOS 15 that September.¹

Mail Privacy Protection. When a user turns it on, which Apple Mail offers on first launch, Apple downloads remote content in emails, including tracking pixels, through its own proxy servers, often before the email is opened. The sender sees an "open" whether or not the person read the email, and sees Apple's IP address instead of the reader's. It applies to anyone reading in Apple Mail, whatever email provider they use.²

iCloud Private Relay. For paying iCloud+ subscribers, Safari traffic is sent through two separate relays, one run by Apple and one by a partner network, so no single party sees both who the user is and which site they visit. Websites see an IP address that maps only to a broad region.¹ Private Relay isn't offered in some countries, including China, for regulatory reasons.³

Hide My Email. iCloud+ users can sign up for services with randomly generated forwarding addresses, so the same person can appear under different email addresses on different sites.^1,4

Why It Mattered

Email open rates had been a core marketing metric for decades, used for A/B testing subject lines, send-time optimization, list cleaning and automated journeys. Apple's Mail apps on iPhone, iPad and Mac accounted for over 46% of email opens in 2020, according to Litmus's email client data, so open rates became inflated and unreliable almost overnight.² Apple's share has grown since: in July 2026, Apple clients accounted for 62% of the opens Litmus measured, including those hidden by Mail Privacy Protection.⁵

Private Relay and Mail Privacy Protection also removed IP addresses as a dependable signal for location and for linking activity across sites and emails. And Hide My Email weakened the email address as a matching key, the identifier many advertisers had turned to after cookies and the IDFA declined.