I have already explained in broad details a while ago how to: Upgrade a Multitenant Environment – Everything at Once https://mikedietrichde.com/2014/08/06/upgrade-pdbs-everything-at-once-full-cdb-upgrade/ Upgrade in a Single-/Multitenant Environment – One/Many at a time or also known as unplug/plug/upgrade strategy https://mikedietrichde.com/2014/08/05/upgrade-pdbs-one-at-a-time-unplugplug/ But one may miss the steps for applying a PSU (Patch Set Update) or BP (Bundled Patch) to a Single-/Multitenant Environment. At first everything will work just the same if you choose the Everything-at-Once strategy as datapatch will adjust all the required things regardless of being executed in a stand-alone or a singe/Multitenant environment. But what happens if you apply a PSU…