I have spamassassin installed some time ago. It's debian package version, default install, just enabled it in /etc/default/spamassassin and also enabled sa-update cron job.
The cronjob executes just fine and updates rules in /var/lib/spamassassin/3.002005/updates_spamassassin_org - the problem is that spamassassin uses rules from /usr/share/spamassassin .
the manual for sa-update says
/By default, sa-update (and spamassassin) expect to find updates in the /var/lib/spamassassin/<spamassassin version> directory,
Which seems to be true true for sa-update only
I solved the problem by copying rules from /var/lib/spamassassin/3.002005/updates_spamassassin_org to /usr/share/spamassassin , but I'm looking for a neat solution that would automate the update process. I'd rather not use script to copy files, as at some point this may break my spamassassin install if they change something I cannot forsee now.