What are the changes that Apple has announced?
At WWDC 2020, Apple announced that iOS 14 will require users to opt in to tracking. This means that the IDFA will only be present for users that explicitly opt in. The expectation is that the percentage of users who opt in will be relatively low.
Confirmation that users will be shown for any app requesting the IDFA
Does Amplitude accept IDFA (Identifier for Advertisers) as the device identifier on iOS?
By default, Amplitude’s iOS SDK uses IDFV (Identifier for Vendor) for the device id, although as the developer you can set anything you want for the device identifier. The SDK includes an option to use IDFA as the device id, but this option will only work if the user has permitted the application to use IDFA.
What are the implications of Apple’s IDFA changes on user tracking?
For all logged in users, there will be no impact, because even if the device id changes, events will continue to merge from devices when the Amplitude platform receives a common user id. This will only potentially have an impact on anonymous users.
For anonymous users, there will be no changes in most cases because the vast majority of our customers are not setting IDFA as the device id. In the cases where an application is already using IDFA as device id, this device id was stored when the SDK was originally initialized, and it will continue to send Amplitude the same id so long as the application remains installed on the device.
If a user deletes and reinstalls an application that does use IDFA for device id, the former device id will not be retained, and a new random device id will be generated unless the user grants the application permission to use IDFA.
For all new application installs, the SDK will accept IDFA if both the user has opted in and the application chooses to use IDFA.
Does Amplitude require IDFA on attribution events?
We do not require IDFA. Amplitude’s attribution API will accept both IDFA and IDFV, and will attempt to match those ids to user events that subsequently come in. In some cases, IDFV will be sufficient to make a match, but some of our customers’ attribution providers only send IDFA, and we will no longer be able to match attribution events unless the user has explicitly opted in to both the referring and installed application.
It is likely that some attribution vendors will stop sending any individual attribution events. It is unlikely that aggregated data will be sent to Amplitude due to the nature of Amplitude and therefore the lack of use, unless customers or attribution vendors can segment that data and use it to set user properties.
How will this impact any outbound integrations?
If you are sending data to any of your outbound integrations, there will be a lower match rate if you use IDFA to match devices between Amplitude and the integration. We recommend that you switch to IDFV or another common identifier instead.