You are definitely being too optimistic :-( In order to implement the new
format, you  need an intelligible delivery  error to begin with.  If your
software says "An  error occurred delivering your mail to  one or more of
its  recipients" and  leaves  it  at that,  your  existing code  probably
doesn't have access to the data that would be needed to implement the new
format. I also  doubt that this will catch up  quickly. Sendmail will use
it, and then  a few products here and there,  maybe. Implementing the new
format  doesn't  provide much  of  a  benefit  to  the site  running  the
software, it just helps  remote list owners. I expect it  would be one of
the last items in the wish lists.
 
  Eric