The change  is indeed for integrity  (not security) reasons. If  you do a
GET with  the NOLOCK option, LISTSERV  is free to continue  modifying the
list. If you  then do a PUT,  changes made by LISTSERV will  be lost, and
noone will be notified. So, when you use NOLOCK, LISTSERV doesn't add the
PUT line. When  you do NOLOCK *and* HEADER, meaning  you will only modify
the header, LISTSERV will write the PUT  line in 1.8b but this is not the
case in the base 1.8a. UBVM is  running an advance release of some of the
1.8b changes and in this respect behaves like 1.8b.
 
  Eric