Db2 12 has been available for over 2 years and many customers have migrated to Db2 12 Function level 500. Function Level (FL) 500 enables all the new Db2 12 base capability. However, changes are needed at the client, and potentially at the server, to exploit FL 501 and above.
Beginning with your migration to Db2 12 for z/OS, you will be embarking on a new journey called continuous delivery. This new way of delivering new features into IBM program products such as Db2 for z/OS will change the migration process and the way you deal with applications going forward.