Error: Node type GeometryNodeAttributeTransfer undefined

[FeeeLyX]

It looks like in the latest version of Blender (I'm using 3.4.1) this Node type became deprecated.
So I've got a runtime error in the solidify_colors_node_group function on line 679.

[BrendanParmer]

3.4 broke a few things I haven't quite had time to fix. I've been meaning to do a rewrite of the node network anyways, since the latest release added some features that would make this a lot less hacky.

In the meantime, 3.0-3.3 should still work. You can also check out Joey Carlino's video on how to do something pretty similar to this add-on if you're just using one material in 3.4.