I attended a Winlink seminar today at Port Isabel near Padre Island.  The information in Andy Oppel's recent report to the ODV is identical to what I was told at the seminar.  Winlink PMBO stations are migrating to a new software, Radio Message Server (RMS).  The new software is reported to be easier to setup and offers more features.  The present Telpac stations will also migrate to new software soon.  Find below a comment from a Winlink official.

"The Winlink 2000 Amateur system is being converted from the current
PMBOs to a "Radio Message Server" system. Each such system will have what is
called "active signal detection," meaning that if another station of any
type is on frequency, it won't transmit. "

David, K5RAV