Path: Community Settings >> General Settings >> Emails & Notifications >> Notification Emails >> Lookback Notification
Lookback Notification emails are sent to members whose ideas have not moved from a particular stage. The administrator of the community can set up the number of inactive days threshold, stages as well as the campaigns on which it can be enabled for.
You can also customise this email by using the strings given into any of the supported languages.
Customizing a string can be easily done by checking the box Customized, edit the text in the below box and Save.