1. If the minimum OPatch version requirement is not met, then upgrade the OPatch after creating a full backup of ORACLE_HOME.
2. If you encounter an error in roll-back of OID one-off patch, please refer to Doc ID 2944818.1 for further details.
3. As more and more patches are applied, OPatch backs up subset patches in the ORACLE_HOME/.patch_storage directory to facilitate a rollback. This might result in performance issues. If you observe such performance issues, please refer to Doc ID 2942050.1 for further details.
4. If you encounter any errors during any phase of applying the patch, contact Oracle Support.