I made these UDIM nodes some time ago, and didn’t really post about it, so I’m doing that now
You can import models with UDIMs, and use these nodes to import the textures and use them on any version of blender with these. To export UDIMs, you don’t need these nodes, only the grid, which I have provided separately for free.
In this video I explain how to do both of these things:
Note: I’m aware of the UDIM branch, but I imagine some people might not be interested in using it right now because it’s still in development. However it is free, unlike my solution.