ABNF for 3.0:
=============

   vcard_entity = 1*(vcard)

   vcard        = [group "."] "BEGIN" ":" "VCARD" 1*CRLF
                  1*(contentline)
        ;A vCard object MUST include the VERSION, FN and N types.
                  [group "."] "END" ":" "VCARD" 1*CRLF

   contentline  = [group "."] name *(";" param) ":" value CRLF
      ; When parsing a content line, folded lines MUST first
      ; be unfolded according to the unfolding procedure
      ; described above.
      ; When generating a content line, lines longer than 75
      ; characters SHOULD be folded according to the folding
      ; procedure described above.

   group        = 1*(ALPHA / DIGIT / "-")

   name         = x-name / iana-token

   iana-token   = 1*(ALPHA / DIGIT / "-")
      ; identifier registered with IANA

   x-name       = "x-" 1*(ALPHA / DIGIT / "-")
      ; Names that begin with "x-" or "X-" are
      ; reserved for experimental use, not intended for released
      ; products, or for use in bilateral agreements.

   param        = param-name "=" param-value *("," param-value)

   param-name   = x-name / iana-token

   param-value  = ptext / quoted-string

   ptext  = *SAFE-CHAR

   value = *VALUE-CHAR
         / valuespec      ; valuespec defined in section 5.8.4

   quoted-string = DQUOTE *QSAFE-CHAR DQUOTE

   NON-ASCII    = %x80-FF
      ; use restricted by charset parameter
      ; on outer MIME object (UTF-8 preferred)

   QSAFE-CHAR   = WSP / %x21 / %x23-7E / NON-ASCII
      ; Any character except CTLs, DQUOTE

   SAFE-CHAR    = WSP / %x21 / %x23-2B / %x2D-39 / %x3C-7E / NON-ASCII
      ; Any character except CTLs, DQUOTE, ";", ":", ","

   VALUE-CHAR   = WSP / VCHAR / NON-ASCII
      ; any textual character


ABNF for 4.0:
=============

   vcard-entity = 1*vcard

   vcard = "BEGIN:VCARD" CRLF
           "VERSION:4.0" CRLF
           1*contentline
           "END:VCARD" CRLF
     ; A vCard object MUST include the VERSION and FN properties.
     ; VERSION MUST come immediately after BEGIN:VCARD.

   contentline = [group "."] name *(";" param) ":" value CRLF
     ; When parsing a content line, folded lines must first
     ; be unfolded according to the unfolding procedure
     ; described in Section 3.2.
     ; When generating a content line, lines longer than 75
     ; characters SHOULD be folded according to the folding
     ; procedure described in Section 3.2.

   group = 1*(ALPHA / DIGIT / "-")
   name  = "SOURCE" / "KIND" / "FN" / "N" / "NICKNAME"
         / "PHOTO" / "BDAY" / "ANNIVERSARY" / "GENDER" / "ADR" / "TEL"
         / "EMAIL" / "IMPP" / "LANG" / "TZ" / "GEO" / "TITLE" / "ROLE"
         / "LOGO" / "ORG" / "MEMBER" / "RELATED" / "CATEGORIES"
         / "NOTE" / "PRODID" / "REV" / "SOUND" / "UID" / "CLIENTPIDMAP"
         / "URL" / "KEY" / "FBURL" / "CALADRURI" / "CALURI" / "XML"
         / iana-token / x-name
     ; Parsing of the param and value is based on the "name" as
     ; defined in ABNF sections below.
     ; Group and name are case-insensitive.

   iana-token = 1*(ALPHA / DIGIT / "-")
     ; identifier registered with IANA

   x-name = "x-" 1*(ALPHA / DIGIT / "-")
     ; Names that begin with "x-" or "X-" are
     ; reserved for experimental use, not intended for released
     ; products, or for use in bilateral agreements.

   param = language-param / value-param / pref-param / pid-param
         / type-param / geo-parameter / tz-parameter / sort-as-param
         / calscale-param / any-param
     ; Allowed parameters depend on property name.

   param-value = *SAFE-CHAR / DQUOTE *QSAFE-CHAR DQUOTE

   any-param  = (iana-token / x-name) "=" param-value *("," param-value)

   NON-ASCII = UTF8-2 / UTF8-3 / UTF8-4
     ; UTF8-{2,3,4} are defined in [RFC3629]

   QSAFE-CHAR = WSP / "!" / %x23-7E / NON-ASCII
     ; Any character except CTLs, DQUOTE

   SAFE-CHAR = WSP / "!" / %x23-39 / %x3C-7E / NON-ASCII
     ; Any character except CTLs, DQUOTE, ";", ":"

   VALUE-CHAR = WSP / VCHAR / NON-ASCII
     ; Any textual character