23/02/2021
"Facebook must change how its pixel collects information and, in some cases, build statistical models in the backend to fill in some gaps of user behaviour. It calls this change ‘Aggregated Event Measurement’ and is a big factor in why pixel events will now be restricted.
Only eight conversion events can be associated with each pixel, which may impact advertising strategies. Attribution windows are also being reduced from 28 days to seven days, which may lead to fewer conversions and less data from which to optimise."
https://www.thedrum.com/opinion/2021/02/22/apple-s-ios-14-update-and-what-it-means-facebook-marketing