Firebase `first_open` event ---> `previous_first_open_count` param logic

Question

Firebase Analytics first_open event sends a parameter previous_first_open_count.

• it starts with value "0" (on lifetime first install / new user).
• and subsequently 1,2,3 .. etc. increments by "1" each time I remove, re-install the app.

Can someone share how the SDK manages to persist the information how often user installed the app (basically triggered first_open) in the past.. AFAIK, once the app is removed, all the app data is deleted.. even the app_instance_id is regenerated each time I remove, re-install the app...

will appreciate to know for both Android and iOS

Answer 1

Actually cannot find any documentation about event_param: previous_first_open_count..

When previous_first_open_count = 0, does it means that user installed application only? Or does it mean, that user have installed and opened app for the first time?

As per the definition ’first_open’ (https://support.google.com/firebase/answer/9234069?hl=en&visit_id=637466094047451258-3073953155&rd=1):

the first time a user launches an app after installing or re-installing it

This event is not triggered when a user downloads the app onto a device, but instead when he or she first uses it. To see raw download numbers, look in Google Play Developer Console or in iTunesConnect.

Supports measuring first_open conversions for users who accept Apple's iOS 14 app-tracking prompt.