Exim

Install the following two brew modules:

$ brew install libidn2

Download and install:
exim-4.94.pkg | June 12, 2020  Must use configure file from this package.  Also must edit php.ini - see below first 'EDIT'
exim-4.93.pkg | Update December 9, 2019 - All versions of Exim previous to version 4.93 are now obsolete.

     EDIT:   Add path to php.ini file so exim can be used as a sendmail replacement/dropin.

$ open -e /usr/local/etc/php/7.4/php.ini

sendmail_path = /usr/local/sbin/sendmail -t -i

Via terminal, create a user called 'email_users' with a password differrent than your mysql root password that will be used for exim and some other modules.

mysql -h 127.0.0.1 -u root -pPASSWORD
CREATE USER 'email_users'@'localhost' IDENTIFIED BY 'password_here';
GRANT ALL ON ecm3.* TO 'email_users'@'localhost'; FLUSH PRIVILEGES; 

     EDIT: Exim configuration file

$ login root
$ nano /usr/local/exim/configure

SERVER_IP = 0.0.0.0
primary_hostname = example.com
hide mysql_servers = localhost::(/tmp/mysql.sock)/ecm3/email_users/password_here

tls_certificate = ${if exists{/private/etc/certificates/${tls_sni}.crt} \ {/private/etc/certificates/${tls_sni}.crt}{/private/etc/certificates/example.com.crt}}

tls_privatekey = ${if exists{/private/etc/certificates/${tls_sni}.key} \ {/private/etc/certificates/${tls_sni}.key}{/private/etc/certificates/example.com.key}}
$ sudo launchctl load /Library/LaunchDaemons/net.captainnet.exim.plist
$ sudo launchctl load /Library/LaunchDaemons/net.captainnet.exim-logrotate.plist

  Dovecot

Download and install:
dovecot-2.3.13.pkg | Updated January 7, 2021 - See update page
dovecot-2.3.11.3.pkg | Updated May 19, 2020 - See update page
dovecot-2.3.10.1.pkg | Updated May 19, 2020 - See update page

Both Exim and Dovecot comes with a generic self signed ssl certificate called 'mailserver.crt' and 'mailserver.key' otherwise the installation would not start. Click for more info for generating your own self signed domain cert.

     EDIT:$ login root
$ nano /usr/local/dovecot/etc/dovecot/dovecot-sql.conf.ext

connect = host=/tmp/mysql.sock dbname=ecm3 user=email_users password=password_here

     EDIT:$ nano /usr/local/dovecot/etc/dovecot/conf.d/10-ssl.conf
Replace 'example1.com' with your domain name you have created a certificate for already during earlier installation.

local_name example1.com {
ssl_cert = </private/etc/certificates/example1.com.crt
ssl_key = </private/etc/certificates/example1.com.key
}

     EDIT:$ nano /usr/local/dovecot/etc/dovecot/conf.d/15-lda.conf

postmaster_address = postmaster@example1.com

$ sudo launchctl load /Library/LaunchDaemons/net.captainnet.dovecot.plist 

  Spamassassin

Download and install:
SpamAssassin-3.4.4.pkg | January 30, 2020 (Security release)

To continue updating spamassassin to version 3.4.4 and running ECM3 on Mojave, it's required that some additional updates are completed. Follow the first section on the updates page.

$ sudo ln -s /usr/local/opt/openssl/lib/libcrypto.dylib /usr/local/opt/mysql/lib
$ sudo ln -s /usr/local/opt/openssl/lib/libssl.dylib /usr/local/opt/mysql/lib

Cpan will require you to go through a series of question of which almost all is "default" except the first one: What approach do you want? Type "sudo" and hit return to continue.       

                 

$ login root
$ cpan
$ install DBI
$ install DBD::mysql
$ install IO::Socket::IP
$ install Net::Patricia
$ install Net::DNS

Login as user:

$ echo 'export PATH=/usr/local/spamassassin/bin:$PATH' >> ~/.bash_profile
    EDIT:
$ open -e /usr/local/spamassassin/etc/mail/spamassassin/sql.cf
Replace the word CHANGE with your password for email_users at three differrent places.

$ sudo /usr/local/spamassassin/bin/sa-update --no-gpg
$ sudo launchctl load /Library/LaunchDaemons/net.captainnet.spamassassin.plist
Reboot computer.

  ClamAV

$ brew install clamav
$ sudo -s
$ chown clamav:admin /usr/local/opt/clamav/share/clamav
$ /usr/local/opt/clamav/bin/freshclam -v
Download and install:
clamav-start.pkg | Updated May 7, 2020

$ sudo -s
$ launchctl load /Library/LaunchDaemons/net.captainnet.clamd.plist
$ launchctl load /Library/LaunchDaemons/net.captainnet.freshclam.plist

  Roundcubemail

Download and install:
roundcubemai-1.4.8.pkg | August 21, 2020 - Security Update
roundcubemai-1.4.7.pkg | August 3, 2020 - Security Update
roundcubemai-1.4.6.pkg | June 17, 2020 - Security Update
roundcubemai-1.4.4.pkg | May 8, 2020 - Security Update
Create database for roundcubemail

mysql -h 127.0.0.1 -u root -pPASSWORD 
CREATE database roundcube; use roundcube; \. /usr/local/share/roundcubemail/SQL/mysql.initial.sql

In the following three instances use your root mysql password.

     EDIT:$ open -e /usr/local/share/roundcubemail/config/config.inc.php

$config['db_dsnw'] = 'mysql://root:password_here@localhost/roundcube';

     EDIT:$ open -e /usr/local/share/roundcubemail/plugins/SAUserPrefs/config.inc.php

$config['sauserprefs_db_dsnw'] = 'mysql://root:password_here@localhost/ecm3';