With word coming that the Phoenix and older Firestorm viewers will be blocked from the SL Grid by the Firestorm Team, it would seem Singularity is in a good position to pick up more users. So, this new release is welcome news to many.
The headline for Singularity is that it gets Media On A Prim (MOAP) with this version. There are 20± more additions to the Singularity Viewer.
See the announcement here: 1.8.1 – Prim Media.