Popular believe is that Oracle Database Smart Flash Cache is available and working with all Oracle database versions in an out of the box manner. However, when using Oracle database 18.104.22.168.2 or less you will have to apply database patch 8974084. To be able to apply patch 8974084 you will have at least have to applied 9654983.
When you are trying to get Oracle Database Smart Flash Cache up and running on an Oracle Database 22.214.171.124.2 or an earlier version you have to apply those patches before you start configuring this option. If the patches are not applied it will not work.