You can always manually edit license.file to remove unwanted licenses. If
you start  LISTSERV with a  1.8c build, it  will ignore 1.8b  licenses as
they are  not valid. If  you start with a  1.8b build, both  licenses are
eligible. You only need  1 more day on the 1.8b  license to make LISTSERV
decide not to  supersede it. There was  also a missing test  in some 1.8b
builds which caused some LAKs not to be superseded when they should have.

  Eric