When archiving a matter there is a box at the bottom of the archive window that allows the previous details to auto populate, if you follow the below steps to archive then today's day will be populated:
From the Main Menu select Matter Archive.
Put in the correct matter.
Select ARCHIVE.
If any WIP is on the file, select if this needs to be written off.
When the Archive details come up there is a box Copy details from the last archive untick this.
Today's date will then populate.
If you don't want today's date, then leave the box ticked and then select ARCHIVE.