The Basics of the Latest Version of Apple’s SKAdNetwork

Jun 16, 2022
By: Jonathan Harrop

Two years ago, Apple unveiled the core pillars of its in-app privacy framework to developers: nutrition labels, the AppTrackingTransparency consumer opt-in framework, and the SKAdNetwork install attribution framework. Last week, it unveiled SKAdNetwork (sometimes called SKAN) 4.0 and for developers seeking to grow their app, it’s good news, though it remains a bit more restrictive than pre-SKAN/ATT standards. Check out our short overview of the major changes.


“The fourth iteration of SKAN is a marked improvement for app install advertisers, and shows Apple is really listening to the app developers that have helped iOS gain such a massive share of the mobile market. There’s still a wide difference between what SKAN can do versus pre-iOS14 measurement, but multiple postbacks will significantly help developers focused on longer-term events and LTV calculations.”

Ben Holmes, GM, Performance at Digital Turbine


Multiple postbacks
This should be welcome news to iOS app install advertisers everywhere. Advertisers (and ad networks) are now allowed to receive up to 3 postbacks (receipts of the install or post-install events) over longer and longer time windows of 0-2 days, 3-7 days, and 8-35 days. Currently, SKAN limits postbacks to a single one, forcing advertisers to choose what conversion event they care about most.

This is huge news for advertisers looking to optimize conversions, as not every KPI occurs immediately, or even within a few days of the initial install. Since advertisers can now do this up to 35 days without delaying their ability to measure earlier events, including the actual install. 

If you’re an advertiser sharing install and post-install data with an ad network and/or DSP, this gives you and your partners more room to optimize for both installs and delayed events. 

Apple hasn’t suddenly turned into a standard MMP though: In order to preserve privacy, SKAN still obfuscates installs by the initial delay AND Apple’s random up-to-24-hour timer, so it’s still effectively impossible to do real-time optimization for SKAN campaigns. 

Privacy Threshold Leniency
Conversion value IDs are changing (and changing names) under SKAN 4.0 to different “grains” of data. They’re still a maximum of 6-bits (64 values), but Apple has declared that using the full 6-bit ID makes it “fine-grained”, and restricted by the existing privacy threshold limitations, which Apple is known to be on the lookout for violators of. 

Now advertisers can set and receive “coarse-grained” conversion values with lower privacy thresholds. There are low, medium, and high versions of this. “Coarse-grained values let advertisers receive limited attribution information when a campaign has a low number of app installations,” says Apple in their documentation. 

Apple calls these new conversion values “Hierarchical conversion values,” but we like HCVs as well. 

More Campaign IDs
One of the hardest squeezes and limitations SKAN put on advertisers was the limit on campaign IDs to 99, with several IDs reserved by Apple, and then more by an ad network for internal purposes (numbers varied widely). This made creative optimization and tracking much harder than it used to be when MMPs placed no real limits on the number of campaign IDs that could be measured. 

With SKAN 4.0, the Campaign ID has been renamed to “‘hierarchical source identifier,” (We like HSI as shorthand for this!) and can communicate much more than just the campaign ID and permits up to 4 digits of information – effectively a tenfold increase in data. 

You can use the last 2 digits to represent the campaign itself (so 00 to 99, or 100 unique values), the second value for location, and the first value for something more detailed like the ad placement. 

For example, your new HSI might be “1337” and refer to a campaign that was a rewarded video campaign (1), targeting a geo like the US West Coast (3), showing a video pre-roll with a particularly great specific dynamic end card experience (37). That’s A LOT more information! 

Other Tidbits
Apple also introduced web-to-app conversions, which is a big bonus for some advertisers, especially those seeking to convert their own users from a news website to their own news app, as long as the destination is the App Store product page. 

We also learned that Apple uses the number of installations as at least one of the metrics it uses to determine whether an app has hit the fabled privacy threshold. This has previously been a total mystery, but still remains a Cupertino secret for the most part. Keeping this data from advertisers until they hit a mystery number does make it a bit more challenging for a new app developer to get off the ground, but fortunately, there are experts like Digital Turbine to help. 

Next Steps
Digital Turbine will of course support all of these changes for iOS campaigns when SKAdNetwork 4.0 goes live “this fall” with iOS 16, and will be testing support throughout this beta period. If you’re interested in using our UA solutions and app growth expertise to experiment and hone your own SKAN 4.0 strategies before, reach out to us!

By Jonathan Harrop
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