RFC 2822, "Internet Message Format", April 2001

Note: This RFC has been obsoleted by RFC 5322

Note: This RFC has been updated by RFC 5335, RFC 5336

Errata ID: 373
Status: Verified
Type: Technical
Publication Format(s) : TEXT
Reported By: Frank Ellermann
Date Reported: 2006-01-10
Verifier Name: Alexey Melnikov
Date Verified: 2010-05-21

Section 3.2.6 says:

   unstructured    =       *([FWS] utext) [FWS]

It should say:

   unstructured    =       *([FWS] utext) (*WSP / obs-FWS)

Notes:

A prominent example is the <subject> defined in section 3.6.5:

subject = "Subject:" unstructured CRLF

Expanding the [FWS] at the end (ignoring <obs-FWS>) results in:

subject = "Subject:" *([FWS] utext) [[*WSP CRLF] 1*WSP] CRLF


Alexey: note that this was fixed in RFC 5322 (which obsoleted RFC 2821) in a slightly different way.

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