Added note to #4 to clarify Reverse DNS entry will need to go from your IP address to your mail subdomain and not to `<yourdomain.com>`.

Added note to #3 to clarify MX Records cannot point to a CNAME or Alias but there is a work around discussed in this commit where you can create a second A record for subdomain.domain.tld and refer it to the IP address of your incoming mail server.

Added one additional bullet point under "Troubleshooting" section based on my experience implementing emailwiz with a New Top-level Domain (NTLD) and sending emails to colleagues at large F500 companies.

Fixes for custom subdomain names

Enforce TLS1.2 connections

Add extra troubleshooting points, minor readability changes

documentation changes

Make README clearer about PTR record

Fixed Tiny Grammar Error

Literally added one letter

Minor change for dovecot.conf to work on v2.3

According to the wiki (https://wiki.dovecot.org/SSL/DovecotConfiguration):

"From version 2.3, you must specify path to DH parameters file using:
ssl_dh=</path/to/dh.pem"

This actually threw an error something along the lines of: "imap-login: Error: Failed to initialize SSL"

remove smtp_tls_CAfile from postfix main.cf

Change Dovecot/Postfix definition

Technically Postfix is responsible for sending *and* receiving mail between *your server and other SMTP servers* (Mail Transfer Agents). Dovecot is only so you can view your mail in email clients on your computer instead of server, which is not really *receiving*. You can have a perfectly functional email system with no IMAP/POP server at all, you'd just have to read your email over SSH or whatever

Added instructions for setting up reverse DNS

Added instructions for setting up reverse DNS

Updated README - typos

GPLv3 proposition