I understand L7 Firewall rules should help you to achieve this.
On the dashboard go the following option and Deny the Category.
Wireless > Firewall & traffic shaping > Select the desired "SSID" > Block applications and content categories - Layer 7 firewall rules > Software and anti-virus updates
I am not aware of any document or information except the following content, stating the "List of Software's" included in this Category.
"The Cisco Meraki cloud-based application signature database is constantly updated to identify new and changing applications, without requiring the administrator to download and install software updates. The Cisco Meraki cloud-based architecture continually learns based on activity from Cisco Meraki's thousands of customers and millions of users, increasing the accuracy and precision of application fingerprints."
Is the L7 Rule not working?
If not you may block the host name. Check the following url for iOS.
For Android I believe above will be challenge as they have various sources. I believe Cisco Meraki EMM may help you on this provided you "OWN" the devices.