It’s post process material.
Navigate to Plugins/PixelizationMaterials/Materials/PostProcess
Create Material Instance of PP_Pixelate and use it in your post process volume.
You can tweak the settings of instance
I didn’t check, but yes it will probably work in newer ue version.
It will ask you to recompile project from sln, since plugin have some c++ code (for palette import and LUT generation). If you don’t need it you can try to remove the source directory from plugin.
You can tweak the settings of instance