we encountered corrupted attachments problem too in version 3.0.7_01
and perl 5.8.2. I looked into sources a bit and solved it by setting
fallback (I18N.pm:sub _GuessCharset) encoding to ‘utf-8’ which is in our
EmailInputEncoding at first position and for EmailOutputEncoding.
But I think this is not Proper™ fix, because there is NO need to
encode/decode binary (msword/pdf) attachments and I think that this
needs to be fixed.