Google this month announced that starting in late 2021, when a user opts out of interest-based advertising or ads personalization, the advertising identifier will not be available on Android devices.
Google says advertisers will receive a string of zeros in place of the identifier.
According to Google, as part of Google Play services update in late 2021, the advertising ID will be removed when a user opts out of personalization using advertising ID in Android Settings.
Google says that to help developers and ad/analytics service providers with compliance efforts and respect user choice, they will be able to receive notifications for opt-out preferences.
This year, Apple released the App Tracking Transparency (ATT) in iOS 14.5 update, limiting the usage of the IDFA (Apple’s IDentifier For Advertisers).
Google, this year, started to limit apps' access to other apps in Android.