Revert back to old version without database backups?

Updating to the latest version of Nextcloud (16.0.3) broke my installation since I do not have a new enough version of PostgreSQL. Upgrading PostgreSQL is not an available option for me to do. Question is: How do I downgrade my Nextcloud installation to an older version without touching the database?
Documentation for Nextcloud states this: “You must have both the database and data directory. You cannot complete restoration unless you have both of these.”

Will I break everything if i just do the following to overwrite the new version with the old?
rsync -Aax nextcloud-dirbkp/ nextcloud/

What is the correct procedure to follow?

Downgrading is not supported and risks corrupting your data! If you want to revert to an older Nextcloud version, make a new, fresh installation and then restore your data from backup.

Taken from here.