The 8-event limit will apply to each domain and includes standard pixel events and custom conversions. You can have multiple pixels and ad accounts connected to a single domain, but you can’t optimize for more than eight events. Read More: 8-Event Limit and Domain Verification Scenarios: iOS 14 Challenges

Optimization, particularly for conversions, will be impacted quite a bit. First, you will be limited to eight conversion events per domain. Second, since Facebook is receiving less data and will be reporting fewer conversions, there is less volume to optimize for. Facebook needs 25-50 conversions per week per ad set to exit the learning phase,… Read more »

All indications are that this shouldn’t impact interest targeting. Attribution, which is only related to ad reporting, also shouldn’t apply to website custom audiences. If a user opts not to be tracked, however, they should be expected to be removed from audiences. Read More: Facebook Advertising Audiences and iOS 14

Once the prompt goes live, you will lose access to the old attribution windows. Until then, you can run reports on historical data for attribution windows including 28-day click and compare those numbers to 7-day click. You should export this data to have access to it later. Read More: Facebook Ads Attribution and iOS 14

Attribution, how Facebook credits an ad with a conversion, changes to 7-day click after the ATT prompt goes live. Prior to January 18, attribution was 28-day click and 1-day view. Beginning January 18, it changed to 7-day click and 1-day view. In addition to 28-day click/view and 7-day view going away once the prompt goes… Read more »