How To Update ClamAV Installation?
From the ClamAV website page on how to upgrade:
If you installed from a package, we suggest you find the approved package from your distro provider and install that. The ClamAV team does not maintain individual packages for every distribution build. If there are no new packages, you have three options:
- Wait
- Build Clam Package
- Install From Source
It is OK to wait because clamav is still working even though it's not the latest version. That warning is more FYI. Also, you don't need to manually run freshclam. If you type
tail -20 /var/log/clamav/freshclam.log
you should see some more info, telling you that the databases etc have been recently (as in, today) updated. When I do this, I see the same warning as you and the next message is don't panic: see https://github.com/vrtadmin/clamav-faq FAQ page So, don't panic.
I do not recommend compiling from source, as it will not be updated through APT, but here is the guide
Summary:
Uninstall the old version sudo apt remove clamav
Download the tar file from the ClamAV website
extract with tar xf clamav* then cd clamav* and then:
./configure
make
sudo make install
then run
sudo freshclam
As always, see the documentation for more help
Zanna's suggestion about installing from source is the correct solution to the problem.
However a more direct answer to the question is to note that 0.99 is the latest version of clamav for Ubuntu 16.04 (the latest version of Ubuntu). See http://packages.ubuntu.com/xenial/clamav .
The warning from the program indicates there is a new version of clamav upstream (i.e., by the developers of clamav). The latest version for the latest version of Ubuntu may actually be a bit older. As the message is just a warning, you can disregard it. If 0.99 has a "serious" security flaw, then a proper patch will most likely be released.
Installing from source is one solution, but you will have to keep it up-to-date manually -- something that we often forget to do.
I don't know much about clamav, but for virus scanners, what you want to keep up-to-date are the virus definitions. Assuming the version you are using can still have the virus definitions updated, you should be fine.