Hexnode lets you enforce OS updates on Supervised iOS devices. For remotely deploying the OS updates:
Navigate to Manage-> Device and select the desired device.
Click on the Actions button and choose the option ‘Update OS’. You will have following options to choose from: Download Only, Download and Install.
When the option ‘Download Only’ is enabled, system updates will be downloaded on the device, but not installed. But the user will be able to manually install it.
To completely block the OS updates, you can configure a proxy server on the network and blacklist the iOS update servers. After this, deploy a Global HTTP proxy configuration to the device using Hexnode, to force all the traffic to go through the Proxy server. As the iOS update servers are blacklisted, the updates will stay unavailable on the devices.