Definition for Division 5.1 reg-5.01 โ€” as in force on 2026-06-01 โ€” F2026C00497 ยท Compilation No. 287 โ€” https://www.legislation.gov.au/F2026C00497/latest/text 5.01 Definition for Division 5.1 In this Division: document includes: (a) a letter; and (b) an invitation, notice, notification, statement or summons, if it is in writing.