Refer to this URL for patching:
Oracle regularly makes patches available to upgrade features, enhance security, or fix problems with supported software. The major types of patches are:
- Interim patches – contain a single bug fix or a collection of bug fixes provided as required
- Interim patches for security bug fixes – contain customer-specific security bug fixes
- Diagnostic patches – intended to help diagnose or verify a fix or a collection of bug fixes
- Bundle Patch Updates (BPUs) – a cumulative collection of fixes for a specific product or component
- Patch Set Updates (PSUs) – a cumulative collection of high impact, low risk, and proven fixes for a specific product or component and Security Patch Updates
- Security Patch Updates (SPU) – a cumulative collection of security bug fixes. SPUs were formerly known as Critical Patch Updates (CPU).
- System Patch – contains several sub-patches in a format that can be used by OPatchAuto.
- Merge Label Request (MLR) – a merge of two or more fixes. MLR creation requires a label for the new set of merged code and a Patch Set Exception