Entry: Attribution—Debugged Apps—App Configuration—Re-Attribution Window
The re-attribution window refers to a timeframe that starts from a user's first install. Any re-installs that occur within the time window (default 3 months) will not be attributed again, while installs that occur after it can be re-attributed as new installs and generate postbacks.
You can set the re-attribution window within the range from 1 month to 24 months.