RFC 5322, "Internet Message Format", October 2008Source of RFC: IETF - NON WORKING GROUP
Area Assignment: app
Errata ID: 2619
Reported By: Dominic Sayers
Date Reported: 2010-11-10
Rejected by: Pete Resnick
Date Rejected: 2011-05-16
Section 3.4.1 says:
It is therefore incumbent upon implementations to conform to the syntax of addresses for the context in which they are used.
It should say:
Implementations MUST conform to the syntax of addresses for the context in which they are used.
The phrase "incumbent upon" is not defined in RFC 2119. If another RFC defines a standard with the force of "MUST", then it is not an option for an implementation to ignore that standard. Therefore, implementations MUST conform to their syntax.
This rewording clarifies the recognition that should be given to the RFCs that inform the particular context of the implementation.
Conforming (or failing to conform) to the syntax of another specification does not affect the interoperability of *this* specification. Therefore, RFC 2119 language is not appropriate. However, even if it could be argued that it was, an erratum is not the appropriate place to make such a change.