One of the major themes for 12c was and is “Simplification” and as part of this is the upgrade simplification for Oracle Identity Manager/Oracle Identity Governance.
Customers who are on 11g have to be on the latest version, 11g R2 PS3, to get error correction support. As long as customers are on this version, it will be supported to upgrade to the latest version (12c PS4) in a single step. This will avoid 11g R2 PS3 upgrade to 12c PS3 to 12c PS4 and customers can directly upgrade from 11g R2 PS3 -> 12c PS4.
Lesser the number of hops, lesser the number of steps, lesser downtime, less risks, less costs to upgrade and quicker path to get to the latest version of the product.
In this regad,product upgrade documentation is updated so that all the information including best practices are available at one place.
Refer to https://docs.oracle.com/en/middleware/fusion-middleware/12.2.1.4/iamup/one-hop-upgrade-oracle-identity-manager.html under the published book: https://docs.oracle.com/en/middleware/fusion-middleware/12.2.1.4/iamup/index.html for more information on this update.
Do reach out to IDM support team if additional information is needed on this topic.