RFC 2046, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", November 1996

Note: This RFC has been updated by RFC 2646, RFC 3798, RFC 5147, RFC 6657, RFC 8098

Errata ID: 6800
Status: Reported
Type: Technical
Publication Format(s) : TEXT
Reported By: Daniel Shahaf
Date Reported: 2021-12-27

Section 5.1.4 says:

                                    In the case where one of the
   alternatives is itself of type "multipart" and contains unrecognized
   sub-parts, the user agent may choose either to show that alternative,
   an earlier alternative, or both.

It should say:

                                    In the case where one of the
   alternatives is itself of type "multipart" and contains unrecognized
   sub-parts, the user agent may choose to either show that alternative,
   show an earlier alternative, or let the user choose which alternative
   to show.

Notes:

The quoted sentence conflicts with the following sentence later in the same section:

What is most critical, however, is that the user not
automatically be shown multiple versions of the same data. Either
the user should be shown the last recognized version or should be
given the choice.

I assume the correction should be as proposed, but other options are conceivable.

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