When a DPN hits, the 21-day clock starts on the issue date, not the delivery...

https://www.beacon-bookmarks.win/when-an-ato-director-penalty-notice-arrives-the-21-day-clock-starts-from-the

When a DPN hits, the 21-day clock starts on the issue date, not the delivery date. Misjudging the distinction between a lockdown and non-lockdown notice can be fatal to your client’s position