Many of our clients are would like to disable automatic updates of the cPanel/WHM server.
Run the following command to check "cpupdate.conf":

/etc/cpupdate.conf

Output is:

[root@cpanel ~]# cat /etc/cpupdate.conf
CPANEL=release
RPMUP=daily
SARULESUP=daily
STAGING_DIR=/usr/local/cpanel
UPDATES=daily
[root@cpanel ~]#

Modify "cpupdate.conf" file and make the following changes:

CPANEL=stable
RPMUP=never
SARULESUP=never
STAGING_DIR=/usr/local/cpanel
UPDATES=never

Save the changes! You're done!