Facebook will have to convince users to disable App Tracking Transparency
App Tracking Transparency is a controversial feature that will automatically opt Apple device users out of ad tracking. Companies will no longer be able to use the ID for Advertisers (IDFA) unless specific permission is granted either through a pop-up notification or in settings.
Apple updated developers with the April 26 deadline after its "Spring Loaded" event. Developers already have to submit App Privacy Labels with any app update stating what tracking an app performs.
Apple says that any app found trying to circumvent App Tracking Transparency will be rejected from the App Store. Apple encourages developers to explain to users why they should allow tracking when the dialog appears.