What happens to Re-Engagement Post-IDFA?

By Henry Wang | March 10, 2021

Is re-engagement possible on iOS 14.5? Let’s find out!

Re-engagement relies on IDFA for targeting. On iOS 14.4 and below, if an app wants to re-engage an existing user base, they can simply upload a device ID (IDFA) list and run a campaign to serve re-engagement ads to those users.

Apple’s iOS 14.5 update introduces two new changes to IDFA sharing:

  1. Apple’s App Tracking Transparency (ATT) will require that apps ask for permission from users to share their IDFA (we expect opt-in rates to be low)
  2. Apple’s SK AdNetwork (SKAN) will become the primary attribution framework for iOS 14.5+ devices and will not pass user level information including IDFA

Now does this mean IDFA is no more? No. It just means that IDFA will be really really hard to get.


  1. Most users will likely opt out of sharing their IDFA, which means most bid requests will not contain IDFA 
  2. SKAN postbacks will never contain IDFA, making it impossible for marketers to track new users who installed your app (your device ID list will quickly become outdated)

What this means for re-engagement is that the pool of users that you can re-engage via IDFA will be very very small. Think about it – you need a big enough device ID list (which will quickly become outdated) AND you need enough users opting in to share their IDFAs for re-engagement to work. So while it’s technically possible to run re-engagement, the scale will be so small that it’s good as dead. 

For this reason, Liftoff will not run re-engagement campaigns on iOS 14.5

So what should you do today?

  1. iOS 14.5 hasn’t kicked in yet so keep on running your iOS re-engagement campaigns while you still have access to IDFA.
  2. When iOS 14.5 kicks in, you’ll want to gradually scale down your re-engagement campaigns as inventory transitions to SKAN (we recommend you shifting your budget to iOS UA campaigns)
  3. And remember you can still run re-engagement campaigns on Android.