It was added in October 2020 and activated by December in v1.0666.
Current version is 1.0770. It went through 3 cycles of testing and seems to work properly.
Although, it works in Easy / Normal / Hard / Hardcore modes only because they allow focusing on farming, which is essential for this system. Soft Iron / Ironman / Speedrun and Nightmare don't have it.
To get the latest release, find the Downloads sections on the mod's homepage here: https://www.patreon.com/thmod