Thank you for the link. Usually I don’t download files from forum links, especially if they are shortened, but I guess I don’t have much of a choice. Earlier offline version links were available on the main site, but it looks like offline versions are gone, and even worse Avast Free Antivirus is gone entirely from there.
And for the update problem I will just post links to the other topics with the update issue similar to mine:
Cannot update Avast or AV database