PDB unplug/plug/patch with PSUs or BPs

This question was posted on the blog a few days ago referring to my previous blog posts describing the two techniques to upgrade in an Oracle Multitenant environment:

• Everything at Once
• One at a Time — via unplug/plug

Question: 

We are planning to upgrade from 12.1.0.2.1 to 12.1.0.2.5.
The plan is to create new 12.1.0.2.5 oracle home and
gradually moving PDB from 12.1.0.2.1 to 12.1.0.2.5.
Should I follow the same steps?
Is there any document for what we want to do?

And luckily there is a MOS Note out there describing the steps:

• MOS Note:2102849.1
  Unplug/Plug on different PSU environments on 12.1.0.2

The part this note is not talking about is the unplug/plugin operations in detail.
But this is something you’ll find here:

–Mike