Not really a single location, as modding is so fluid right now, but the change was mentioned in the dev blog when it was made, as well as here on the Discourse.
http://stonehearth.net/steam-unstable-develop-2795/
#Important note to Mod developers
@yshan has made changes to the mod version so all existing mods must be updated before they will work.
Developers, please update the version in your manifest.json to 2. Mods with version 2 should maintain compatibility with older game versions, so you do not need to maintain 2 mod versions.
##Notes from the blog:
Hey everyone, thank you all for your bug reports! We’ve got a few fixes for you on our Steam…