Nice problem came up today when a customer informed us about a problem with his Tobit David.fx server. All mails arriving since the January 1st 2010 had the year changed to 2000. We just had a little debugging session what causes this and finally found out that the IMAP server returned:

[..]INTERNALDATE "05-Jan-10 13:33:52 UT"[..].

Following RFC3501 date-year must be a 4-digit field. Even in the old RFC2060 from 1996 date_year must be 4-digit field.

msg-att-static = "ENVELOPE" SP envelope / "INTERNALDATE" SP date-time \
"RFC822" [".HEADER" / ".TEXT"] SP nstring /
"RFC822.SIZE" SP number /
"BODY" ["STRUCTURE"] SP body /
"BODY" section ["<" number ">"] SP nstring /
"UID" SP uniqueid ; MUST NOT change for a message
date-time = DQUOTE date-day-fixed "-" date-month "-" date-year SP time SP zone DQUOTE
date-year = 4DIGIT