This document provides guidance on using Oracle Data Guard Standby-First Patch Apply to apply patches and patch bundles to physical standby databases before applying them to the primary database. It allows validating patches on the standby first with minimal risk to the primary. The process involves installing patches on the standby, evaluating them, then installing on the primary. It is supported for certified interim patches up to one year apart between primary and standby. SQL installation is delayed until all databases have the same binaries.