Looking for Tips on using the Donor Portal in RENXT

I am considering setting up the Donor Portal option in RENXT. Can anyone tell me if the updates that donors make to their profiles override the existing data that is there? We like to save the prior records because it helps with duplicate processing and backstory about our donors/alumni.

I saw there is a way to review updates that donors made and even change the data back if we wanted to, but I didn't see any screenshots or notes indicating if the prior data was saved on the record.

Any other helpful items about the portal are also appreciated. Thanks!