How iOS 14.5 Changed Ad Attribution Forever
TL;DR Apple shipped iOS 14.5 on April 26, 2021 with App Tracking Transparency (ATT), which forced apps to ask permission before accessing the IDFA. Roughly 96% of US iPhone users initially opted out (Flurry Analytics, 2021), and opt-in rates have since climbed to approximately 35-37% as of 2025 (Adjust Q2 2025), gutting the cross-app data […]