Starting with the launch of iOS 14.5, apps have to request authorization from the user in order to access the Identifier For Advertiser (IDFA) of the device (opt-in). Until now, access to IDFA was allowed by default (opt-out). This has a big impact on the app ad and attribution industry.
Learn more in my blog post on the inovex website:
https://www.inovex.de/de/blog/app-tracking-transparency-and-idfa-in-ios-14-5/