anchor.diff:  
   VOLUME ["/mail"]
   
  -EXPOSE 993
  -
  +EXPOSE 993 995
  
positive.code:       dovecot-imapd \
        dovecot-lmtpd \
        dovecot-mysql \
        dovecot-sieve \
        dovecot-managesieved \
   && rm -rf /var/lib/apt/lists/*
  
negative.code:     'ssl_key=</ssl/ssl_private_key.pem' \
      'ssl_protocols=!SSLv3 !SSLv2' \
      'ssl_cipher_list=TLSv1+HIGH !SSLv2 !RC4 !aNULL !eNULL !3DES @STRENGTH' \
   && /opt/editconf.py /etc/dovecot/conf.d/20-pop3.conf \
      pop3_uidl_format="%08Xu%08Xv" \
   && /opt/editconf.py /etc/dovecot/conf.d/20-imap.conf \
      imap_idle_notify_interval="4 mins" \
   && sed -i "s/#port = 143/port = 0/" /etc/dovecot/conf.d/10-master.conf \
  