According to a new report from Forbes, Apple has begun rejecting apps and app updates that do not comply with iOS 14.5's new App Tracking Transparency rules.
See also: iOS 14.5 public beta 5 released! What changes does it bring?

Starting with iOS 14.5, apps will have to ask users for permission to access the iPhone's advertising identifier, or IDFA, which allows for tracking for advertising purposes. To continue to be on the App Store, apps will have to comply with the rules once iOS 14.5 is released. These rules also prevent apps from using other methods of tracking users, which is already causing problems for some developers.
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Several apps have already been rejected (Heetch, Radish Fiction, InnoGames, and others). When Apple rejects an app, developers see a message informing them that the app is being rejected because it uses data to create a unique identifier for the purpose of tracking users. The message also lists the data that is being collected.
Additionally, Apple blocks apps that use fingerprinting techniques to collect datafor the purpose of creating a user profile, as this allows tracking of users even without an advertising identifier.

Apple believes that if a user opts out of using IDFA for ad tracking, they automatically opt out of all other tracking methods. According to Apple’s App Store rules, app developers cannot collect data from a device for the purpose of identifying it, and developers are responsible for all tracking code in their apps, including any third-party SDKs they use. So they need to be very careful if they want their apps on the company’s app store.
See also: Apple's App Tracking Transparency feature is coming this spring!
If Apple rejects an app, developers will have to make the necessary updates to the app to make it compliant with the rules.
It's unclear when iOS 14.5 will be released, but we've had six betas so far, so it's likely to be released sometime in the spring. Given that Apple has already started rejecting app updates due to App Tracking Transparency, we can assume that iOS 14.5 will be released very soon.
Source: MacRumors
