%% You should probably cite rfc7817 instead of this I-D.
@techreport{ietf-uta-email-tls-certs-04,
    number =    {draft-ietf-uta-email-tls-certs-04},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-ietf-uta-email-tls-certs/04/},
    author =    {Alexey Melnikov},
    title =     {{Updated TLS Server Identity Check Procedure for Email Related Protocols}},
    pagetotal = 8,
    year =      2015,
    month =     aug,
    day =       6,
    abstract =  {This document describes TLS server identity verification procedure for SMTP Submission, IMAP, POP and ManageSieve clients. It replaces Section 2.4 of RFC 2595.},
}