1. need to locate where the SSL for Exim should to be:
grep "tls_certificate\|tls_privatekey" /etc/exim/exim.conf
tls_certificate = /etc/exim/ssl/exim.crt
tls_privatekey = /etc/exim/ssl/exim.key

2. now we can update the SSL with valid certificate for our hostname:
file /etc/exim/ssl/exim.key should store private key for your domain
file /etc/exim/ssl/exim.crt should store certificate + ca-bundle for your domain

3.Now time to update Dovecot with the following lines or replace them:
ssl_cert =

In the file /libraries/joomla/database/database.php
Need to find the string $this->_table_prefix = $table_prefix; and put the following code after it:

@mysql_query("SET NAMES 'cp1251'", $this->_resource);
@mysql_query( "set session character_set_server=cp1251", $this->_resource );
@mysql_query( "set session character_set_database=cp1251", $this->_resource );
@mysql_query( "set session character_set_connection=cp1251", $this->_resource );
@mysql_query( "set session character_set_results=cp1251", $this->_resource );
@mysql_query( "set session character_set_client=cp1251", $this->_resource );

or, in the case with UTF-8:

@mysql_query("SET NAMES 'utf8'", $this->_resource);
@mysql_query( "set session character_set_server=utf8", $this->_resource );
@mysql_query( "set session character_set_database=utf8", $this->_resource );
@mysql_query( "set session character_set_connection=utf8", $this->_resource );
@mysql_query( "set session character_set_results=utf8", $this->_resource );
@mysql_query( "set session character_set_client=utf8", $this->_resource );

The default configs are stored here:
/usr/local/mgr5/etc/templates/default/

If you want to build your own one, just copy it to one level up, to

/usr/local/mgr5/etc/templates/

for example cp -pv /usr/local/mgr5/etc/templates/default/nginx-vhosts-ssl.template /usr/local/mgr5/etc/templates/

More details and how-to guides on the original site

Original local.cnf is stored here:
/etc/mail/spamassassin/local.cf

yum remove -y ovh-rtm-binaries ovh-rtm-metrics-toolkit beamium noderig

First need create the repo:

nano /etc/yum.repos.d/maria.repo

And past the repo info:

# MariaDB 10.3 CentOS repository list - created 2019-07-30 21:01 UTC
# http://downloads.mariadb.org/mariadb/repositories/
[mariadb]
name = MariaDB
baseurl = http://yum.mariadb.org/10.3/centos7-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1

After that time to make the upgrade:

yum update -y

And fix the issues, takes after upgrade steps:
mv /etc/my.cnf /etc/my.cnf.back; mv /etc/my.cnf.rpmnew /etc/my.cnf
service mariadb restart;systemctl status mariadb.service -l
mysql_upgrade
service mariadb restart;systemctl status mariadb.service -l

systemctl disable named.service;\
systemctl disable mysql.service;\
systemctl enable pdns.service;\
systemctl enable mariadb.service;\
ln -sv /usr/local/mgr5 /panel;\
ln -sv /usr/share/spamassassin /etc/spamassassin;\
mkdir /etc/old.mysql-configs; cp -pRv /etc/my.cnf* /etc/old.mysql-configs/

Where to check:
whmapi1 domainuserdata domain=somedomain.com
grep -Rl somedomain.com /var/cpanel/users/
grep -Rl somedomain.com /var/cpanel/userdata/
grep -Rl www.somedomain.com /etc/apache2/
grep -Rl somedomain.com /etc/*domains

After that:
/scripts/updateuserdomains
/scripts/updateuserdatacache
/scripts/rebuildhttpdconf
/scripts/restartsrv_httpd

quick fix:
chown root:root /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/bin/soft
chmod 4555 /usr/local/cpanel/whostmgr/docroot/cgi/softaculous/bin/soft

yum install -y gcc-c++ make
curl -sL https://rpm.nodesource.com/setup_10.x | sudo -E bash -
yum install nodejs