==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.9
- Deployed with iRedMail Easy or the downloadable installer? No
- Linux/BSD distribution name and version: CentOS 7.7
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx):  Apache 2.4
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Today I upgraded to 0.9.9 and noticed the iRedAdmin in now a service listening on 7791.
This is nice.

Given I am using Apache, the upgrade process does not change the Apache config from mod_wsgi to mod_proxy_uwsgi

If you don't make the changes shown in this post:
iRedMail Support Post

Then you are still running iRedAdmin as a child process under Apache.
This does work, but the new iredadmin.service is not being used.

So after having discovered the answer elsewhere, I found the post above that was the same solution.  Nice !!

This is what I did (with more detail):

Install the Apache Module from EPEL

yum install mod_proxy_uwsgi

Enable the new module

echo 'LoadModule proxy_uwsgi_module modules/mod_proxy_uwsgi.so' >> /etc/httpd/conf.modules.d/00-proxy.conf

Modify the default Apache iredadmin.conf file - /etc/httpd/conf.d/iredadmin.conf
Comment out the first 4 lines, leaving only the Directory section.
My last 2 lines above were already commented because they were moved to a vhost.

#WSGISocketPrefix /var/run/wsgi
#WSGIDaemonProcess iredadmin user=iredadmin threads=15
#WSGIProcessGroup iredadmin

#AddType text/html .py

<Directory /var/www/iredadmin/>
    <IfVersion < 2.4>
        Order deny,allow
        Allow from all
    </IfVersion>
    <IfVersion >= 2.4>
        Require all granted
    </IfVersion>
</Directory>

#Alias /iredadmin/static "/var/www/iredadmin/static/"
#WSGIScriptAlias /iredadmin "/var/www/iredadmin/iredadmin.py/"

In my vhost config file.   (or you can put it in your /etc/httpd/conf.d/iredadmin.conf)

....
    Alias                  /iredadmin/static "/var/www/iredadmin/static/"
    ProxyPass           /iredadmin/static  !
    ProxyPass           /iredadmin "uwsgi://127.0.0.1:7791"
#  WSGIScriptAlias   /iredadmin "/var/www/iredadmin/iredadmin.py/"
....

Remove the old Apache Module

yum erase mod_wsgi

Restart Apache

systemctl reload httpd

Done.

AND... my Apache restart (or stop) used to take minutes to occur.  Now it is instant.  Yippee !!

Rob.