Revert to upstream
The maintenance overhead of maintaining the package ourselves is too high. It will require the review of all packages using clamav/app-antivirus-core including Kaspersky. File locations change and so does the user/group of the daemon, I believe.
There is another gotcha in that the loading of signatures in some update changed so new signatures are loaded into memory then swapped with the current signatures which are then junked. This doubles the memory usage when there are new signatures. There is a new parameter which controls this which defaults to on. We'd need to add it to any existing installation and pref it off. Otherwise we'd need to increase the minimum spec of the machine. I guess we could script the value of the parameter depending on the available memory?