Everything you learned about email open rates before 2021 needs re-examining. Apple’s Mail Privacy Protection inflated average open rates by 18 percentage points overnight — and most guides still haven’t caught up. This complete 2026 guide covers what email open rates actually mean now, the 9 tips that genuinely improve performance, current benchmarks from Klaviyo and MailerLite, and the metrics that matter more than open rate in the post-iOS 15 era.