Just as RFC 1123 section 5.2.14 amended the 822 syntax for date, RFC 1342
amended the syntax for phrase and comment (and in the latter case with
far less impact on parsers, since an encoded-word still matches atom (in
word) in a phrase and ctext in a comment).
Actually, no. There was a difference in intent between the two. 1123 was
imposing new requirements on existing protocols, 1341 and 1342 were not
doing so. MIME implementation was not mandatory (as a matter of standards
compliance) for existing user agents.
Keith