Receiving a DPN means the 21-day clock starts ticking from the issue date....

https://www.lawyersweekly.com.au/sme-law/44139-what-solicitors-need-to-know-when-a-client-receives-a-director-penalty-notice

Receiving a DPN means the 21-day clock starts ticking from the issue date. Distinguishing lockdown versus non-lockdown scenarios is critical for your client’s legal strategy