in my game, the email doesn't say anything about using a floppy/zip drive in regards to the daily hash codes. it still says the original text of "write it down on a note and attach to the top of the drive box".
The email I have on my save from Dr Bao does describe the floppy disc/zip drive system. Odd that you didn't get one. Did you play from an old save, or did you start a new one? Mine was a new save