In accordance with Zihe Jia‘s response to my first message on this announcement post,
ever since iOS 14.0, every new user was being assigned the IDFV as their distinct_id.
We have previously and still do retrieve their IDFA manually and write it to the user profile as a custom property, but that’s all we do with it. All our calls to identify() simply pass the existing distinctId value retrieved using Mixpanel.mainInstance().distinctId. We aren’t manually setting IDFA as the distinctId.
If it helps to know, we do have the iAd and AdSupport frameworks installed, and we have since well before iOS 14. Before iOS 14, mixpanel defaulted to using IDFA as the distinctId. Then it became IDFV since iOS 14, as explained in the comment I linked above. But now all of a sudden it’s the IDFA again. We have remained on SDK version 2.7.1 through the timeline in question.
We are still on 2.7.1 of the SDK but all of a sudden I’m seeing new users that download our iOS app being created in mixpanel with their IDFA as the distinct_id. Could you help me understand what could be happening here? The code in my app that handles all things mixpanel hasn’t changed at all since my previous comment in that thread 6 months ago.
I don’t mean to bloat this post but I feel it may be easier to help me if I add more context. The core reason I’m looking for clarification on this is that we are planning to enable user accounts for our app pretty soon. Up until now we have not used accounts and persisted data locally. Once we release the user accounts feature, we will want to enable Identity Merge for our project so that a single human using multiple devices under their one account will be tracked as a single MTU. Given my understanding of how ID Merge works, it doesn’t seem like a good idea to have a device’s idfa ever become part of an identity cluster. It would be helpful if I could gain some clarity on how turning on ID Merge might affect our existing user profiles, some of which have IDFA and some IDFV as their distinct ID.
I’d really appreciate any guidance or thoughts on this.