Despite having set the updates to "manual", this time "my" Avast Free antivirus seems to have updated itself automatically; and also with no notifications/questions/warnings at all.
My latest (manual, as usual) update was a couple of months ago and today, when checking the settings, I found out that "Avast Free Antivirus is up to date" with version 23.12.6094, which obviously I never installed.
This is not what I expected, because I disabled automatic updates.
What is the reason for such a behaviour (which actually occurred another time, about two years ago)?
Is there a reliable way to permanently prevent automatic updates?