Archive all directory logs except today with find and gzip

find /var/log/srv/auth-server -mtime +1 -type f -iname *.log -exec gzip -9 {} ';'

-mtime +1 - find files older than 1 day
-exec gzip {} ';' - executes a gzip command on a found file, the original file will be removed. The ';' at the end may be replaced by + or by \;