“The post pack goes to the networks but not the advertiser with ios 15 if the post back goes to the advertiser you can at the very least verify they're telling the truth with bonkers considering i think david you imagine uh until all this time you you just have to take the platform's word for it even pre-att.”

With ATT, Advertisers Have To Trust Platforms — iOS 15 Postbacks Finally Let You Verify

Before iOS 15, SKAdNetwork postbacks went to ad networks (Facebook, Google, TikTok) but NOT to the advertiser — meaning advertisers had to take platform-reported numbers on faith. TikTok was caught silently changing null conversion values to zero (different semantics). iOS 15 postback delivery to advertisers (via their MMP) finally enables verification that platform-reported data matches reality — a fundamental accountability shift in mobile advertising.