Reapplying to Harvard

[jzducol]

Before 2019, the file was maintained both in a hard copy format and an electronic format, although the latter may not contain all of the information in the file. Harvard switched to an online reading system beginning with the 2019 cycle, in which all file materials are maintained electronically.

The above information was revealed in recent court document. Its almost a certainty all applications since 2015 are easily retrievable. Any reapplication I imagine will be cross referenced with earlier ones.
If by now OP has not had significant change in application from last year (like winning major awards, etc) I doubt just changing a sup essay in EA is going to make the difference.