The updated packages fix two packaging problems and a security vulnerability:
A Denial-of-Service (DoS) vulnerability may occur when scanning a specially crafted email file as a result of excessively long scan times. (CVE-2019-15961)
The first packaging issue, in the configuration of clamav-daemon.socket, leads to freshclam and amavis complaining about not being able to access clamd socket.
The second packaging issue, in the names of systemd services, leads to warnigs at the installation/update of clamav and clamd.