A new Italian law disposition require to keep login logoff information for at least 6 months

I've modified the cron
find /opt/zimbra/log/ -type f -name \*.log\* -mtime +8 -exec rm {} \; > /dev/nul ...

to ind /opt/zimbra/log/ -type f -name \*.log\* -mtime +190 -exec rm {} \; > /dev/nul ...

but this has been reset during upgrade to 6.0.5

Is there another supported way to increase just the audit.log for more than 6 months?

Why don't zimbra use the log rotation on linux boxes?
AleX