Af now handles multipart messages internally, displaying each body part (or passing it to the external program) separately. This means that the "mime-saver" variable is now redundant, and has been removed. Each body part is saved, or passed to to external commands (like "print-command") separately too. Each body part is properly decoded as it is handled.
Af now handles encapsulated messages marked as being in "message/rfc822" or "message/news" format properly, removing the encapsulation and displaying the encapsulated message. Af will also attempt to rebuild a "message/partial" message, if all the parts of the message are either in the current buffer, or encapsulated in messages in the current buffer.
The "Content-Disposition" header is now handled correctly. Af will insert a default Content-Disposition header whenever you send a file, or check any values you care to enter. When reading mail, af will warn you about any attachments found, and give you the choice of either viewing them, saving them to a file, or skipping them.
When you print, pipe, or save the bodies of a set of messages so that partial messages are rebuilt, af will detect messages that are parts of a single message, and only write the rebuilt message out once.
The new commands "previous-section" (M-{ or {) and "next-section" (M-} or }) are now supported in typeout. When displaying the headers and body parts of a multipart message to typeout, af lets you use these commands to move between the body parts without having to exit typeout and open the message again.
The new commands "open-body-parts" and "open-body-parts-other-window" allow you to view each body part (or encapsulated message) of a message as messages in a new buffer. This command also works for mail digests, so the obsolete "explode-digest" command has been removed.
The new "Body-Parts" minor mode indicates that a buffer contains the body parts of another message. When a buffer is in "Body-parts" mode, then the contents of the "body-part-line-format" variable are used to display the details of each body part, rather than the "header-line-format" variable.
The new command "insert-buffer" allows you to insert the contents of one buffer into another. This can be handy for dealing with buffers containing the expanded body parts of a message.