The Substance Plugin has been updated and released on GitHub. The Marketplace plugin should be updated soon, so keep your eyes open!
Github Link: https://github.com/Allegorithmic/UnrealEngine
If you have 404 errors using Github: Unreal Engine 4 on GitHub - Unreal Engine
This release is meant to be compatible with 4.12.5
[Blueprint] Added blueprint node to return the name of a substance graph instance
[Blueprint] Added blueprint node to return the name of the parent factory of a graph instance
[Editor] Added editor thumbnail icon for Substance Instance Factory objects in the content browser
[Editor] Added editor thumbnail icon for Substance Graph Instance objects in the content browser
[Bug Fix] When no roughness or metallic textures are in use, materials will now apply specular textures if available.
[Bug Fix] Fixed occasional crash on packaged builds