Tommi wrote (2023-01-27):

 CN>> (Just curious - I currently use JAM and FMail so I don't need it.)

 TK> 'ftools maint -D' seems to renumber JAM base here. How do you purge
 TK> messages in JAM without renumbering?

AFAIK JAM has no "unique message identifier" (UMSGID) like Squish. If you purge messages from the beginning, BaseMsgNum can be set:

    This field determines the lowest message number in the index file.
    The value for this field is one (1) when a message area is first
    created. By using this field, a message area can be packed (deleted
    messages are removed) without renumbering it. If BaseMsgNum contains
    500, the first index record points to message number 500.

    BaseMsgNum has to be taken into account when an application
    calculates the next available message number (for creating new
    messages) as well as the highest and lowest message number in a
    message area.

If you delete messages in the middle you get holes without renumbering.

Solution: use Squish (as in the software).

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