[mlmmj] bug: Index is never incremented

Hello:

I just realized that I have a problem with the lists that are set up to use
1.4.0 -- the index is never incremented. For example, the list that has
received several new messages in the past week still has the same index value
from September:

$ ls -al index
-rw-------. 1 mlmmj mlmmj 4 Sep 28 04:54 index
$ cat index
1173

All the messages since September go out from the list as:
tools+bounces-1174...

Everything still works for regular mail delivery, but this is obviously a
problem.

Happy to help troubleshoot this further.

-K