MIME::Lite predates Perl 5.8 which supports Unicode and UTF-8. But it’s easy to get MIME::Lite to work with Unicode bodies and subjects.
To attach a plain text part to a message, with a string which contains unicode characters, use:
$msg->attach( Type => 'text/plain; charset=UTF-8', Data => encode("utf8", $utf8string), );
To set the subject of a mail from a string containing unicode characters, use:
use MIME::Base64; my $msg = MIME::Lite->new( ... Subject => "=?UTF-8?B?" . encode_base64(encode("utf8", $subj), "") . "?=", ... );
Note that the above methods also work even if the strings do not contain unicode characters, or do not have the UTF-8 bit set.
It would be better to change MIME::Lite such that subject and data strings are accepted and the above code happens inside MIME::Lite. I’ve filed a bug report. It was rejected.