microapp
The first link is dead.
The second link refers to changing update settings and not disabling the service.
If the sevice is disabled, Defender will not update.
Link fixed. Not clear on the exact effect of turning off automatic Windows updates, vs. completely disabling the service. If the Defender needs the WU service for a manual update, then that would probably break it.
You can turn off Windows automatic updates in Pro, so it's not really necessary to disable the service. WU is the usual mechanism for providing Defender updates, but you can still get the Defender updates manually, or by Task Scheduler using a scheduled scan.
But really the whole point to my originally even mentioning this, was the possibility that Microsoft or another provider has a silent update at work here. I was using Defender as an example of something that can update, even with WU auto update turned off.