There was never really an announcement for Version 6.1.0 of the Blender exporter, other than a post at the end of a long topic, & and a tweet.
There has been a minor update to 6.1.1 today as well, to work with slightly different names of properties in PBR between 4.0 & 4.1.
Here are both change logs:
Blender Exporter Version 6.1.1
14 May 2019
Support for exporting to either BJS 4.0 or 4.1 regarding names of properties, which changed names
Make PBR materials the default
Blender Exporter Version 6.1.0
- 11 May 2019
- Added support for Subsurface, Anisotropic, Clear Coat, & sheen from Principled node for PBR
- Added tangents when also using custom split normals
- Added several generic .env files for when PBR is output
- Made changes reflecting the final API for Blender 2.80