Hello @Eugene,
This update description with path /var/www/ is for Composer-based installations and for manual installation update. If your Bacularis was installed in a different way, these two methods will not work with your Bacularis instance and in this case this is correct that you don't have files in that /var/www/ path.
If you installed Bacularis using binary packages, the available version in free repositories is currently 5.0.0. In the subscription repositories it is always latest version (currently 5.7.0).
All the update procedures (excluding the Docker method) you can find on the Updating Bacularis chapter in the documentation:
https://bacularis.app/doc/brief/updating.html
Best regards,
Marcin Haba (gani)