==== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.7 MARIADB edition
- Linux/BSD distribution name and version: Ubuntu 16.04
- Store mail accounts in which backend LDAP/MySQL/PGSQL):  MySQL
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

For security reasons, I would like to regularly change the passwords that iRedMail uses. I can easily change the postmaster password using the web GUI, but I am struggling to find where all of the MySQL passwords are stored and to determine how to change them.

So far I have found that iRedMail stores passwords in the following locations:

root -> /root/.my.cnf
amavisd -> /etc/amavis/conf.d/50-user
iredadmin -> /root/.my.cnf-iredadmin
iredapd -> /root/.my.cnf-iredapd
roundcube -> /opt/www/roundcubemail/config/config.inc.php
sogo -> /etc/sogo/sogo.conf
vmail -> /root/.my.cnf-vmail
vmailadmin -> /root/.my.cnf-vmailadmin

Is there a procedure to update all of these passwords?