You could update the modules regularly by following the instructions on this wiki page
https://senbox.atlassian.net/wiki/display/SNAP/Update+SNAP+from+the+command+line
Disabling the update can be achieved by settings two properties:
-J-Dplugin.manager.check.interval=NEVER
must be added into the etc/snap.conf file to the default_options parameter. This is the update you are referring to.
There is a second update check. This checks only for new major releases (e.g. 6.0) and displays a notification.
snap.versionCheck.interval=NEVER
This property must be added to the etc/snap.properties file