Meta iOS 14.5 App Tracking Transparency (2021)
Apple required opt-in for tracking; Meta signal loss, Aggregated Event Measurement and shorter attribution windows followed.
DateApr 26, 2021
PlatformMeta Ads
TypePrivacy
Who it affectsAll advertisers
What happened
Apple’s iOS 14.5 required apps to ask users for permission to track them across other apps and websites (App Tracking Transparency). Many users declined, so Meta lost a large share of conversion signals, introduced Aggregated Event Measurement and changed default attribution windows. Meta later said the changes would cost it billions in revenue.
Who it affected
All advertisers.
What it means for marketers today
Server-side tracking with the Conversions API and better first-party data help recover lost signals.
Related
See the full Meta Ads History: From Facebook Ads to Andromeda