It's better to have deleted messages without a hash than to hash invalid message numbers.
This can be used to address a (renumbered?) message base that Kirkman
shared with me with "Invalid Message number" chksmb warnings from hash
entries with message numbers > than the base's last_msg.
From Rob Swindell (on Debian Linux) to Git commit to main/sbbs/master on Sun Mar 17 00:34:50 2024