Starting with iOS 14, when obtaining an IDFA, a user consent dialog will be displayed by AppTrackingTransparency.framework, and this is scheduled to become a requirement in the future.
*Reference: User Privacy and Data Use (Apple Developper)
Due to the change described above, you will need to update to the latest supported SDK.
For details, please refer to the following page in the integration manual: "Other Support" > "The effects of iOS 14 specification changes and a request to update to the latest SDK".
In addition, you can check the same details in "Announcement" when you log in to the console.