What You Should Know About SKAdNetwork:  

1. Loss of IDFA eliminates the concept of user-level tracking. 
2. Attribution Postbacks will be delivered by Apple directly to the end points defined by Ad Networks. This forces all networks to prepare and adapt to these changes quickly.
3. Each Ad Network must register directly with Apple and obtain an Ad Network ID. Each ID will be limited to 100 campaign IDs which will be used to track campaign performance down to publishers, placements, source IDs etc. This reduces the level of granularity available with current setups.
4. No redirects will be allowed. This poses a significant challenge in terms of tracking real-time performance, delivery of campaigns, and detecting fraud.
5. Postbacks will be delayed by up to 24 hours, which eliminates the ability to measure click-to-install time or event time.