[BOOKINGDATE:+1day{%A, %e %B, %Y}] - optional date offset and display format. The offset can be any plus or minus any number of days and the display can be any valid PHP strftime format string.
[MODIFYDATE:{%A, %e %B, %Y}] - last booking modification date/time, the display can be any valid PHP strftime format string.
[PAYMENTDATE:{%A, %e %B, %Y}] - most recent payment date