I am looking for the Patch Finder for Windows ArcGIS Desktop version 10.4.x.
I suppose you can use the following link to download the Patch Finder:
And the available patches can be found here:
Is there a Patchfinder available for 10.5?
Esri Support Downloads
Xander Bakker's URL leads to patchfinder that works on 10.5.1. Esri Support Downloads page is not very helpful in finding the patchfinder.
It looks like this link works for getting to the 10.4 patch finder
Esri Support 10.4 (10.4.1)
Is that what you're looking for?