The experimental 2.15 is now the default build. The only difference from 2.14 is that it uses Cloud Save.
As for 2.16 it has some multithreading disabled to debug some issues on Windows 7. Please note that Windows 7 is not supported and eventually it will probably stop working at some point in the future. I will try my best to keep it working but please be prepared.
I've also added Vulkan to the experimental build. You may launch in Vulkan by adding
-force-vulkan
to the launch arguments.