SquirrelMail

According to RFC1521, the type and subtype in the Content-Type header
should be matched as case-insensitive. While most clients use all lower
case, some, such as Pegasus Mail, do not. This prevents proper inclusion
of the attachment (+) flag when displaying the message headers for email
generated by such clients. Using strtolower during the check for
'multipart' and 'mixed' in functions/mailbox_display.php fixes the problem
in the current stable version. While I'm not using the development
version, the code there also appears case sensitive and should probably be
modified as well.

If you have any questions, you can email me at rpollei@crinet.com.