Here's the latest text:
Note: If any line begins with the string "From", it is strongly
suggested that either the Quoted-Printable or Base64 MIME encoding
be applied. If Quoted-Printable is used, at least one of the
characters in the string should be encoded using the hexadecimal
coding rule. This is because many mail transfer and delivery
agents treat "From " (the word "from" followed immediately by a
space character) as the start of a new message and thus insert a
right angle-bracket (>) in front of any line beginning with "From"
to distinguish this case, invalidating the signature.
--
Thomas Roessler <roessler(_at_)does-not-exist(_dot_)org>