Currently, there's a lot of game mechanics based crashes and savegame state loading crashes. 90% of the time there's nothing I can do to fix them.
As 0.15.13 is coming out soon with a lot of code changes. I've decided to put some fixes back into the WIP2 that is for 0.15.12b. Frankly, most of these fixes are a step back to the previous WIP1 so I'm keeping the version number.
Meanwhile, I'm moving the WIP3 to 0.15.13 compatibility. Since final 0.15.13 changes aren't set this will have to wait a bit.