SKAN 4 Explained: A Plain-English Guide for App Marketers

By Intent+ Team · March 18, 2026 · 14 min read · 2,300 words

SKAN 4 is Apple's privacy-preserving attribution framework for iOS apps. It tells advertisers how their campaigns performed without revealing which specific user did what. Here's what it means in plain English — and how it affects your Apple Ads campaigns day to day.

What Is SKAN 4?

SKAdNetwork 4 (SKAN 4) is Apple's privacy framework that aggregates ad performance data across three postback windows instead of one, adds crowd anonymity tiers, and supports hierarchical conversion values — coarse and fine-grained — to give advertisers richer signal while preserving user privacy.

How Postback Windows Work

SKAN 4 delivers data in three windows after install: 0–2 days (Window 1), 3–7 days (Window 2), and 8–35 days (Window 3). Each window sends a separate postback with the conversion value your app reported during that period.

Conversion Values — Fine-Grained and Coarse

Window 1 can carry a 6-bit fine-grained conversion value (0–63) and a coarse value (low/medium/high). Windows 2 and 3 carry only coarse values, subject to crowd anonymity thresholds.

Crowd Anonymity Tiers

SKAN 4 withholds conversion data below a minimum campaign volume threshold. Low-volume campaigns receive only coarse values or no postback at all. Understanding these tiers is essential for structuring campaigns to receive actionable signal.

What SKAN 4 Means for Your Apple Ads Campaigns

Conversion value mapping, campaign consolidation to cross anonymity thresholds, and the shift from install-level optimisation to event-level optimisation are the three operational changes every Apple Ads team needs to make.

Frequently Asked Questions

Difference between SKAN 3 and SKAN 4, how to map conversion values, what happens when crowd anonymity blocks data, and how to work with MMP partners on SKAN 4 implementation.