You can manage Android OS update policy in Headwind MDM, in configuration details, parameter "System update".
Unfortunately Android doesn't allow to disable OS updates completely. The following options are available:
Default - do not change the OS update policy
Immediately - update OS (and reboot the device) immediately after the phone receives the on-the-air update, without user consent.
Scheduled - update OS without user consent at certain time (usually at night). This is the most appropriate option.
Postponed - request user consent for the update within 1 month after the device downloads the update; if the user consent is not received within a month, updates the device anyway. Not recommended because it depends on the user's action.
Note: OS update policy can only be applied if Headwind MDM launcher is installed as a device owner.