blender27-v3.5.1: YafaRay v3.5.1 (2020-07-13) for Blender 2.79:

Binaries for YafaRay Blender-Exporter v3.5.1 and older for Blender 2.7x are stored in the (now archived) old YafaRay Blender-Exporter repository here:

https://github.com/YafaRay/Blender-Exporter/releases