As yet, there has been no discussion on this issue.
John C Klensin wrote:
In RFC 2821bis-01, Section 4.2.1 (Reply Code Severities and Theory), in
the description of the generic 4yz category, described the desired
action in terms of what the client "is encouraged to" do. I was
persuaded in an off-list exchange that this can reasonably be changed to
"SHOULD" and -01 reflects that change. For 5yz, there was a similar
construction that indicates that the client "is discouraged from"
repeating the request. I was less confident about changing that to
"SHOULD NOT", so the "is discouraged" text remains in -01.
Question: Should the 5yz description be changed to use "SHOULD NOT".
If not, is "SHOULD" in the 4yz description reasonable?