Mar 17 06:56:25 webserver1 amavis: (01668-01) (!!)WARN: all primary virus scanners failed, considering backups
So how do we "Update"? Is the Virus Database being updated still/automatic? And do we get the "Upgrade" with the Ubuntu Release Upgrade?
This has nothing to do with your Clamd-Version or the database-version.
Amavis canīt reach clamd as defined in @av_scanners. Make sure that the clamd is running and the socket-file in your amavis-config for the @av_scanners matches the LocalSocket defined in your clamd.conf