There is a sa-update.timer which can start daily the sa-update.service
You can enable this timer by:
systemctl enable sa-update.timer
systemctl start sa-update.timer
In /etc/sysconfig/spamd You can enable or disable some functionality of sa-update.service:
* SPAM_SA_COMPILE
* SPAM_SPAMD_RESTART
* SPAM_AMAVISD_RESTART
