I'm puzzled: my Windows 10 system running Avast free seems to have updated to 20.1 despite my setting the update option in 19.8 as "Ask when an update is available". Even stranger, I didn't notice it doing the update; I think it must have been picked up when I rebooted for other reasons. Well, I was going to update anyhow.....
Another user reported the same thing. It looks like in some cases update settings are not honored.
No Auto Update here, but I have Program Updates set to Manual. Plus I didn't even let it update to 19.9, so that is what it is currently complaining about, not 20.1.
Yet another looking over my shoulder spammie ad in the UI.
OK, I also got auto-updated despite "Ask when an update is available" being selected.
However, I also avoided restarting and while still running 19.7:
1. Saved my Avast settings.
2. Disabled my network interface so 20.0 would not be able phone home.
3. Then let Avast restart.
4. (I figured it was better to let the 20.0 update complete before uninstalling; more of a chance for the uninstaller to get confused by the in-between state of affairs.)
5. Uninstalled Avast.
6. Reinstalled 19.7 with the offline installer. [19.7.2388 (build 19.7.4674.0)]
7. Restored my Avast settings from the save file.
8. Changed "Ask when an update is available" to "Manual Update."
9. (There are some more restarts in this process.)
10. Reenabled my network interface.
11. Awhile later Avast requested a Restart.
12. After the restart, the build number changed: 19.7.2388 (build 19.7.4674.552). (I think this is still a program update disobeying my selection.)
13. So far, this seems to be holding off 20.0.
-dwh