Hi, As we are focusing on S/MIME for internal use in the company and therefore need S/MIME support for otrs. We managed to import and use our certificates, but we have a lot of problems with MIME encoded emails which have attachments. We recognized also some problems with signing regarding MIME-Headers and CR/LF, which seem to be an openssl smime problem. The reception of signed emails in otrs doesn't work sometimes if there is an attachment included. In this case we got an "single part MIME message." The major difference I noticed is that in this case the email is not encoded multipart, but as one part and the attachement is included in the signed data. Regardless whether this is correct in MIME-standard it works with outlook 2002, but not with otrs. ArticleCheckSMIME.pm looks for multipart-type. Fixing this, the correct signing is shown, but as the attachement is not recognized during import the email, it is not shown. Any ideas to fix it or for a workaround? An example is attached. Thanks in advance and regards Thomas