With Apple officially confirming that its new, opt-in data tracking prompts for apps will be rolling out to iOS users from next week, Facebook has today issued a reminder to developers and advertisers as to how they can prepare, and what, exactly, is likely to be impacted as a result of the change.

Apple's controversial ATT, or 'AppTrackingTransparency' update, will see users served with new prompts in all apps on iOS devices, which will explicitly ask them to approve that app's data tracking - or stop it from sharing their in-app activity.

That's expected to have a significant impact on ad targeting capacity, as more users choose to block in-app tracking, limiting the amount of information available to understand how people are engaging with different elements.

Following Apple's confirmation, Facebook has posted a long explainer on the various impacted elements, and how businesses can prepare for the update.

First off, Facebook says that it will now implement a range of new measurement protocols to help mitigate the expected impacts, including Apple’s SKAdNetwork API and Facebook’s Aggregated Event Measurement. Facebook says that these elements will continue to enable the measurement of campaign results - with limitations. Those limitations will most specifically apply to app install campaigns, pixel tracking, and attribution windows, all in varying capacity. You can read more about the specifics of those impacts here.

Facebook also warns that advertisers "can expect to see changes in Facebook’s business and advertising tools, including ad set up, audience selection, delivery, measurement, and reporting".

"For example, if you’re an app advertiser, you’ll need to run iOS 14 mobile app install advertising within one ad account and will be limited to nine campaigns per app; and if you use web events to optimize and measure your campaigns, you will be limited to optimizing for no more than eight events on each domain that you own. We plan to share future guidance that may update these limitations as we innovate to operate with restricted, aggregated, and delayed data."

Facebook also provides some direct advice for advertisers, with a specific focus on app developers looking to promote on the platform.

Facebook says that app advertisers need to:

• Update to the Facebook SDK version 8.0 or above. If you use a Mobile Measurement Partner, confirm you’re using the version of their SDK that supports Apple’s SKAdNetwork API.
• Set up your conversion schema in Events Manager to optimize for App Events, Value and Mobile App Installs with Automated App Ads.
• Plan to create iOS 14 app install campaigns with one ad account per app, nine campaigns per app and five ad sets per campaign of the same optimization type.

​Advertisers using Web Events meanwhile, need to:

​Facebook has also flagged a range of updates that will be implemented, in varying capacity, from next week, as Apple's new changes are rolled out.

Those changes will include:

• The removal of 28-day click-through, 28-day view-through, and 7-day-view through attribution windows for campaigns
• Limiting the number of website events that can be used for optimization to 8
• The removal of Lift Measurement for iOS 14 Mobile App Install and Mobile App Events campaigns
• Advertisers will have to create separate iOS 14 app install campaigns with one ad account per app, nine campaigns per app and five ad sets per campaign of the same optimization type
• Mobile app custom audiences for inclusion will be removed

You can read more about the specifics on each here.

Basically, there's a broad range of ways in which the iOS 14.5 update could impact your Facebook ad campaigns, and we won't know for some time just how significant those impacts will be, but Facebook says that it is working on options and solutions to help advertisers maintain ad effectiveness.

Additionally, Facebook also notes that it's developing new ways to create ad tracking and data tools that better align with Apple's enhanced focus on data privacy. 

"While we have expressed concerns about Apple’s approach, we support giving people more control over how their data is used to improve advertising relevance. Toward this end, we are investing in new approaches to privacy-enhancing technology and building a personalized advertising ecosystem that relies on less data, while helping to ensure a level playing field for both large and small businesses."

It's an uncertain time for Facebook marketers, with those using in-app data likely to be most directly impacted by the update. If that's you, then it's worth checking out Facebook's more in-depth overview, with more specific information on the pending impacts, and how you can prepare for each.

Again, we won't know how many users will switch off data tracking in each app until it actually happens, so while it could make things much more difficult for targeting, it may also not be as significant as expected (as some early reports have suggested), which could end up minimizing the impacts.

But it may well be significant. Either way, it's worth taking note of your data sources, and considering how to best prepare now, ahead of next week's change. 

Facebook says that it will continue to provide guidance for advertisers as the impacts unfold, and further development of optional solutions continues.