yes it is, and that's the reason why the automatic updates is the default option. so if user changed to manual updates, it should be fine just to remind there is a new version
Well, as far as I know one of the most important precautionary
"rules", when talking software, is to avoid hasty upgrades to new versions, which notoriously can always bring some problems. Especially with programs that are crucial for the proper functioning of the system. Which does not mean, of course, "never upgrade" but just means... wait a little, learn what the upgrade provides, check if problems or regressions are reported and then upgrade. So the user who chooses manual updates, in my humble opinion, does not necessarily deserve to be considered a "bad" user or a user who needs some kind of "education".
I totally agree with your statement
"it should be fine just to remind there is a new version".
In this case, however, Avast did not tell me
"there is a new version" but it told me
"there is a new version in your computer", already installed and running, whether you like it or not. Which is quite different.
