From the FAQ page (http://www.lsoft.com/lsv-faq.html#Sect28):

28. Is LISTSERV Year 2000 compliant?

For most systems, year 2000 support will be provided in version 1.8d
(contingent to operating system support for year 2000 of course).
There were all of 6 changes to make, of which 3 were to print yyyy
instead of yy and 2 were to provide a more reasonable default for yy
in command input (and one was a breakage). For VM, this will probably
not be done until 1999. Problem 1 is that we don't want to fix the
REXX code that is scheduled to go away before year 2000, and problem
2 is that we still have a lot of S/370 customers to support, whereas
the year 2000 capable version of VM only supports XA.

Francoise