-.TH MHFIXMSG %manext1% 2018-01-14 "%nmhversion%"
+.TH MHFIXMSG %manext1% 2019-03-31 "%nmhversion%"
.
.\" %nmhwarning%
.
.RB [ \-replacetextplain " | " \-noreplacetextplain ]
.RB [ \-fixboundary " | " \-nofixboundary ]
.RB [ \-fixcte " | " \-nofixcte ]
+.RB [ \-checkbase64 " | " \-nocheckbase64 ]
.RB [ \-fixtype
.IR mimetype ]
.RB [ \-outfile
programs that parse MIME messages.
.PP
The
+.B \-checkbase64
+switch enables a check of the encoding validity in base64-encoded
+MIME parts. The check looks for a non-encoded text footer appended
+to a base64-encoded part. Per RFC 2045 \(sc6.8, the occurrence of
+a "=" character signifies the end of base-64 encoded content. If
+none is found, a heuristic is used: specifically, two consecutive
+invalid base64 characters signify the beginning of a plain text
+footer. If a text footer is found and this switch is enabled,
+.B mhfixmsg
+separates the base64-encoded and non-encoded content and places
+them in a pair of subparts to a newly constructed multipart/mixed
+part. That multipart/mixed part replaces the original base64-encoded
+part in the MIME structure of the message.
+.PP
+The
.B \-fixtype
switch ensures that each part of the message has the correct MIME type
shown in its Content-Type header. It may be repeated. It is
\-reformat text parts that are not text/plain
\-fixboundary outermost multipart part
\-fixcte multipart or message part
+\-checkbase64 base64 encoded parts
\-fixtype all except multipart and message parts
.fi
.RE
.RB ` \-noreplacetextplain '
.RB ` \-fixboundary '
.RB ` \-fixcte '
+.RB ` \-checkbase64 '
.RB ` \-changecur '
.RB ` \-noverbose '
.fi