Our analysis is based on the ID chosen at the time of SDK generation, so if you are using IDFV then you will not be affected by these changes.
The impact of the iOS 14 update for customers using IDFA will be a significant, but gradual, decrease in traffic as soon as the update is rolled out. As a result, we recommend that you use a different mobile ID, such as IDFV, for example.
When a user chooses to block the IDFA/AAID, they will, by default, be in OPT-OUT. Please note that there is a sub-option in our SDK, called ignoreLimitedAdTracking, which is equivalent to using the UUID if the IDFA/AAID is unavailable.
By using the UUID, you will be able to perform a measurement in exempt mode in case of tracking refusal, provided that you respect all the conditions set by local authorities.
However, we do not recommend the use of advertising identifiers. Indeed, it represents a risk from a legal point of view because it is dedicated to advertising (Apple and Google deny any responsibility). Secondly, this new opt-in feature on iOS 14 makes the IDFA unavailable in the vast majority of cases.